diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4d2d173..93ea6be 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `shaping` subcommand and extra (#36).
 - `fontwerk` extra (#37).
 - `notofonts` extra (#37).
+- `com.thetypefounders/check/features_default_languagesystem`: Checks if a default languagesystem statement is present in feature files and warns if the compiler will not insert one automatically (https://github.com/fonttools/fontbakery/issues/4011)
 
 ### Changed
 
@@ -31,6 +32,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `com.google.fonts/check/unique_glyphnames`: The check now takes into account that OpenType-CFF2 fonts with `post` table format 3 contain no glyph names, and will yield SKIP (#38).
 - `com.google.fonts/check/STAT_in_statics`: The check now skips fonts that do not have a `STAT` table (#38).
 - `com.google.fonts/check/family_naming_recommendations`: Two validations of PostScript name were moved out of this check and into `com.adobe.fonts/check/postscript_name` which yields FAIL (#62).
+- `com.google.fonts/check/cjk_not_enough_glyphs`: This check is now only run when a font has CJK codepages or ranges declared in the `OS/2` table. Other CJK-related checks are run on fonts with a minimum of 150 CJK glyphs (https://github.com/fonttools/fontbakery/issues/3846).
+- `com.google.fonts/check/family/panose_familytype` and `com.google.fonts/check/family/panose_proportion`: Failures have been downgraded to warnings (https://github.com/fonttools/fontbakery/issues/4192).
 
 ### Fixed
 
@@ -38,6 +41,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `com.google.fonts/check/fontvalidator`: ERROR caused by attempting to run FontValidator before checking if it's installed (#30).
 - `com.google.fonts/check/mandatory_glyphs`: Improved the check's resilience to edge cases that could result in ERRORs (#38).
 - `-L`/`--list-checks` option that can be used with subcommands. Previously this option only worked if a path to an input file was also provided in the command line (#35).
+- Summary statistics on HTML reporter (https://github.com/fonttools/fontbakery/issues/3997).
 
 ## [0.1.0] - 2023-06-11
 
diff --git a/Lib/openbakery/constants.py b/Lib/openbakery/constants.py
index f5c0c14..91a4a57 100644
--- a/Lib/openbakery/constants.py
+++ b/Lib/openbakery/constants.py
@@ -575,7 +575,6 @@ class WindowsLanguageID(enum.IntEnum):
     "Hangul Syllables": 56,
     "CJK Unified Ideographs": 59,
     "CJK Strokes": 61,
-    "Yi Syllables": 83,
 }
 
 
@@ -602,8 +601,6 @@ class WindowsLanguageID(enum.IntEnum):
     [0x31C0, 0x31EF],  # CJK Strokes
     [0xF900, 0xFAFF],  # CJK Compatibility Ideographs (CJK Strokes)
     [0x2F800, 0x2FA1F],  # CJK Compatibility Ideographs Supplement (CJK Strokes)
-    [0xA000, 0xA48F],  # Yi Syllables
-    [0xA490, 0xA4CF],  # Yi Radicals
 ]
 
 OFL_BODY_TEXT = """
diff --git a/Lib/openbakery/profiles/fontwerk.py b/Lib/openbakery/profiles/fontwerk.py
index 486c61b..8c5b33f 100644
--- a/Lib/openbakery/profiles/fontwerk.py
+++ b/Lib/openbakery/profiles/fontwerk.py
@@ -39,6 +39,8 @@ def leave_this_one_out(checkid):
         "com.google.fonts/check/version_bump",
         "com.google.fonts/check/production_glyphs_similarity",
         "com.google.fonts/check/name/line_breaks",
+        "com.google.fonts/check/fontdata_namecheck",
+        "com.google.fonts/check/meta/script_lang_tags",
         # The following check they may need some improvements
         # before we decide to include it:
         "com.google.fonts/check/family/italics_have_roman_counterparts",
diff --git a/Lib/openbakery/profiles/googlefonts.py b/Lib/openbakery/profiles/googlefonts.py
index a8f5cb0..8cb8de5 100644
--- a/Lib/openbakery/profiles/googlefonts.py
+++ b/Lib/openbakery/profiles/googlefonts.py
@@ -5650,9 +5650,9 @@ def com_google_fonts_check_cjk_vertical_metrics_regressions(
 
 @check(
     id="com.google.fonts/check/cjk_not_enough_glyphs",
-    conditions=["is_cjk_font"],
+    conditions=["is_claiming_to_be_cjk_font"],
     rationale="""
-        Hangul has 40 characters and it's the smallest CJK writing system.
+        Kana has 150 characters and it's the smallest CJK writing system.
 
         If a font contains less CJK glyphs than this writing system, we inform the
         user that some glyphs may be encoded incorrectly.
@@ -5660,12 +5660,12 @@ def com_google_fonts_check_cjk_vertical_metrics_regressions(
     proposal="https://github.com/googlefonts/fontbakery/pull/3214",
 )
 def com_google_fonts_check_cjk_not_enough_glyphs(ttFont):
-    """Does the font contain less than 40 CJK characters?"""
+    """Does the font contain less than 150 CJK characters?"""
     from .shared_conditions import get_cjk_glyphs
 
     cjk_glyphs = get_cjk_glyphs(ttFont)
     cjk_glyph_count = len(cjk_glyphs)
-    if cjk_glyph_count > 0 and cjk_glyph_count < 40:
+    if cjk_glyph_count > 0 and cjk_glyph_count < 150:
         if cjk_glyph_count == 1:
             N_CJK_glyphs = "There is only one CJK glyph"
         else:
@@ -5673,8 +5673,8 @@ def com_google_fonts_check_cjk_not_enough_glyphs(ttFont):
 
         yield WARN, Message(
             "cjk-not-enough-glyphs",
-            f"{N_CJK_glyphs} when there needs to be at least 40"
-            f" in order to support the smallest CJK writing system, Hangul.\n"
+            f"{N_CJK_glyphs} when there needs to be at least 150"
+            f" in order to support the smallest CJK writing system, Kana.\n"
             f"The following CJK glyphs were found:\n"
             f"{cjk_glyphs}\n"
             f"Please check that these glyphs have the correct unicodes.",
diff --git a/Lib/openbakery/profiles/os2.py b/Lib/openbakery/profiles/os2.py
index d05e295..0f63af8 100644
--- a/Lib/openbakery/profiles/os2.py
+++ b/Lib/openbakery/profiles/os2.py
@@ -35,7 +35,7 @@ def com_google_fonts_check_family_panose_proportion(ttFonts):
         )
 
     if not passed:
-        yield FAIL, Message(
+        yield WARN, Message(
             "inconsistency",
             "PANOSE proportion is not the same across this family."
             " In order to fix this, please make sure that"
@@ -71,7 +71,7 @@ def com_google_fonts_check_family_panose_familytype(ttFonts):
         )
 
     if not passed:
-        yield FAIL, Message(
+        yield WARN, Message(
             "inconsistency",
             "PANOSE family type is not the same across this family."
             " In order to fix this, please make sure that"
diff --git a/Lib/openbakery/profiles/shared_conditions.py b/Lib/openbakery/profiles/shared_conditions.py
index e3a5559..f7e7bc5 100644
--- a/Lib/openbakery/profiles/shared_conditions.py
+++ b/Lib/openbakery/profiles/shared_conditions.py
@@ -503,18 +503,21 @@ def unicoderange(ttFont):
 
 
 @condition
-def is_cjk_font(ttFont):
+def is_claiming_to_be_cjk_font(ttFont):
     """Test font object to confirm that it meets our definition of a CJK font file.
 
-    The definition is met if any of the following conditions are True:
+    We do this in two ways: in some cases, we are testing the *metadata*,
+    i.e. what the font claims about itself, in which case the definition is
+    met if any of the following conditions are True:
+
       1. The font has a CJK code page bit set in the OS/2 table
       2. The font has a CJK Unicode range bit set in the OS/2 table
-      3. The font has any CJK Unicode code points defined in the cmap table
+
+    See below for another way of testing this.
     """
     from openbakery.constants import (
         CJK_CODEPAGE_BITS,
         CJK_UNICODE_RANGE_BITS,
-        CJK_UNICODE_RANGES,
     )
 
     if not has_os2_table(ttFont):
@@ -541,17 +544,23 @@ def is_cjk_font(ttFont):
             if os2.ulUnicodeRange3 & (1 << (bit - 64)):
                 return True
 
-    # defined CJK Unicode code point in cmap table checks
-    cmap = ttFont.getBestCmap()
-    for unicode_range in CJK_UNICODE_RANGES:
-        for x in range(unicode_range[0], unicode_range[1] + 1):
-            if int(x) in cmap:
-                return True
-
     # default, return False if the above checks did not identify a CJK font
     return False
 
 
+@condition
+def is_cjk_font(ttFont):
+    """
+    The `is_claiming_to_be_cjk_font` condition looks up the font's metadata to see if
+    it is claiming to be a CJK font. But the metadata may be wrong, and the correctness
+    of the metadata is something what we want to check!
+    We also want to know if the font really is a CJK font, i.e. it contains a
+    significant number of CJK characters. We say that *this* definition is met if the
+    font has more than 150 CJK Unicode code points defined in the cmap table.
+    """
+    return len(get_cjk_glyphs(ttFont)) > 150
+
+
 @condition
 def get_cjk_glyphs(ttFont):
     """Return all glyphs which belong to a CJK unicode block"""
diff --git a/Lib/openbakery/profiles/ufo_sources.py b/Lib/openbakery/profiles/ufo_sources.py
index 8bd364f..97f8b99 100644
--- a/Lib/openbakery/profiles/ufo_sources.py
+++ b/Lib/openbakery/profiles/ufo_sources.py
@@ -1,10 +1,13 @@
+import re
+
 from openbakery.callable import check, condition
-from openbakery.status import ERROR, FAIL, PASS, WARN
+from openbakery.status import ERROR, FAIL, PASS, SKIP, WARN
 from openbakery.section import Section
 from openbakery.message import Message
 from openbakery.fonts_profile import profile_factory
 from openbakery.utils import exit_with_install_instructions
 
+
 profile = profile_factory(default_section=Section("UFO Sources"))
 
 UFO_PROFILE_CHECKS = [
@@ -16,6 +19,7 @@
     "com.google.fonts/check/designspace_has_default_master",
     "com.google.fonts/check/designspace_has_consistent_glyphset",
     "com.google.fonts/check/designspace_has_consistent_codepoints",
+    "com.thetypefounders/check/features_default_languagesystem",
 ]
 
 
@@ -303,5 +307,48 @@ def com_google_fonts_check_designspace_has_consistent_codepoints(designSpace, co
         yield PASS, "Unicode assignments were consistent."
 
 
+@check(
+    id="com.thetypefounders/check/features_default_languagesystem",
+    conditions=["ufo_font"],
+    rationale="""
+        The feature file specification strongly recommends to use a
+        `languagesystem DFLT dflt` statement in your feature file. This
+        statement is automatically inserted when no `languagesystem`
+        statements are present in the feature file, *unless* there is
+        another `languagesystem` statement already present. If this is
+        the case, this behaviour could lead to unintended side effects.
+
+        This check only WARNs when this happen as there are cases where
+        not having a `languagesystem DFLT dflt` statement in your feature
+        file is technically correct.
+
+        http://adobe-type-tools.github.io/afdko/OpenTypeFeatureFileSpecification.html#4b-language-system
+    """,
+    proposal="https://github.com/googlefonts/fontbakery/issues/4011",
+)
+def com_thetypefounders_check_features_default_languagesystem(ufo_font):
+    """Check that languagesystem DFLT dflt is present in the features.fea file."""
+
+    if ufo_font.features.text is None:
+        yield SKIP, "No features.fea file in font."
+    elif not ufo_font.features.text.strip():
+        yield PASS, "Default languagesystem inserted by compiler."
+    else:
+        tags = re.findall(
+            # pylint: disable-next=line-too-long
+            r"languagesystem\s+([A-Za-z0-9\._!$%&*+:?^'|~]{1,4})\s+([A-Za-z0-9\._!$%&*+:?^'|~]{1,4})",  # noqa E501
+            ufo_font.features.text,
+        )
+
+        if len(tags) > 0 and ("DFLT", "dflt") != tags[0]:
+            tags_str = ", ".join([" ".join(t) for t in tags])
+            yield WARN, Message(
+                "default-languagesystem",
+                f"Default languagesystem not found in: {tags_str}.",
+            )
+        else:
+            yield PASS, "Default languagesystem present or automatically inserted."
+
+
 profile.auto_register(globals())
 profile.test_expected_checks(UFO_PROFILE_CHECKS, exclusive=True)
diff --git a/Lib/openbakery/reporters/html.py b/Lib/openbakery/reporters/html.py
index c92faa9..920eb0a 100644
--- a/Lib/openbakery/reporters/html.py
+++ b/Lib/openbakery/reporters/html.py
@@ -43,12 +43,11 @@ def get_html(self) -> str:
             section_stati_of_note = (
                 e for e in section["result"].elements() if e != "PASS"
             )
-            if all([self.omit_loglevel(s) for s in section["result"].elements()]):
-                continue
             section_stati = "".join(
                 EMOTICON[s] for s in sorted(section_stati_of_note, key=LOGLEVELS.index)
             )
-            body_elements.append(f"<h2>{section_name} {section_stati}</h2>")
+            if not all([self.omit_loglevel(s) for s in section["result"].elements()]):
+                body_elements.append(f"<h2>{section_name} {section_stati}</h2>")
 
             checks_by_id: Dict[str, List[Dict[str, str]]] = collections.defaultdict(
                 list
diff --git a/tests/profiles/googlefonts_test.py b/tests/profiles/googlefonts_test.py
index cd5ada0..095bd5d 100644
--- a/tests/profiles/googlefonts_test.py
+++ b/tests/profiles/googlefonts_test.py
@@ -4171,12 +4171,15 @@ def test_check_cjk_not_enough_glyphs():
 
     ttFont = TTFont(TEST_FILE("montserrat/Montserrat-Regular.ttf"))
     msg = assert_results_contain(check(ttFont), SKIP, "unfulfilled-conditions")
-    assert msg == "Unfulfilled Conditions: is_cjk_font"
+    assert msg == "Unfulfilled Conditions: is_claiming_to_be_cjk_font"
 
     # Let's modify Montserrat's cmap so there's a cjk glyph
     cmap = ttFont["cmap"].getcmap(3, 1)
     # Add first character of the CJK unified Ideographs
     cmap.cmap[0x4E00] = "A"
+    # And let's declare that we are a CJK font
+    ttFont["OS/2"].ulCodePageRange1 |= 1 << 17
+
     msg = assert_results_contain(check(ttFont), WARN, "cjk-not-enough-glyphs")
     assert msg.startswith("There is only one CJK glyph")
 
diff --git a/tests/profiles/os2_test.py b/tests/profiles/os2_test.py
index 6bf64ba..3706f34 100644
--- a/tests/profiles/os2_test.py
+++ b/tests/profiles/os2_test.py
@@ -60,7 +60,7 @@ def test_check_family_panose_proportion(mada_ttFonts):
     mada_ttFonts[0]["OS/2"].panose.bProportion = incorrect_value
 
     assert_results_contain(
-        check(mada_ttFonts), FAIL, "inconsistency", "with inconsistent family."
+        check(mada_ttFonts), WARN, "inconsistency", "with inconsistent family."
     )
 
 
@@ -78,7 +78,7 @@ def test_check_family_panose_familytype(mada_ttFonts):
     mada_ttFonts[0]["OS/2"].panose.bFamilyType = incorrect_value
 
     assert_results_contain(
-        check(mada_ttFonts), FAIL, "inconsistency", "with inconsistent family."
+        check(mada_ttFonts), WARN, "inconsistency", "with inconsistent family."
     )
 
 
diff --git a/tests/profiles/ufo_sources_test.py b/tests/profiles/ufo_sources_test.py
index fc681e1..725acc6 100644
--- a/tests/profiles/ufo_sources_test.py
+++ b/tests/profiles/ufo_sources_test.py
@@ -8,6 +8,7 @@
 from openbakery.codetesting import (
     assert_PASS,
     assert_results_contain,
+    assert_SKIP,
     CheckTester,
     TEST_FILE,
 )
@@ -171,3 +172,73 @@ def test_check_designspace_has_consistent_codepoints():
     assert_results_contain(check(designspace), FAIL, "inconsistent-codepoints")
 
     # TODO: Fix it and ensure it passes the check
+
+
+def test_check_default_languagesystem_pass_without_features(empty_ufo_font):
+    """Pass if the UFO source has no features."""
+    check = CheckTester(
+        ufo_sources_profile, "com.thetypefounders/check/features_default_languagesystem"
+    )
+
+    ufo, _ = empty_ufo_font
+
+    assert_SKIP(check(ufo), "No features.fea file in font.")
+
+
+def test_check_default_languagesystem_pass_with_empty_features(empty_ufo_font):
+    """Pass if the UFO source has a feature file but it is empty."""
+    check = CheckTester(
+        ufo_sources_profile, "com.thetypefounders/check/features_default_languagesystem"
+    )
+
+    ufo, _ = empty_ufo_font
+
+    ufo.features.text = ""
+
+    assert_PASS(check(ufo))
+
+
+def test_check_default_languagesystem_pass_with_features(empty_ufo_font):
+    """Pass if the font has features and no default languagesystem statements."""
+    check = CheckTester(
+        ufo_sources_profile, "com.thetypefounders/check/features_default_languagesystem"
+    )
+
+    ufo, _ = empty_ufo_font
+
+    ufo.features.text = "feature liga { sub f i by f_i; } liga;"
+
+    assert_PASS(check(ufo))
+
+
+def test_check_default_languagesystem_warn_without_default_languagesystem(
+    empty_ufo_font,
+):
+    """Warn if `languagesystem DFLT dflt` is not present in the feature file,
+    but other languagesystem statements are."""
+    check = CheckTester(
+        ufo_sources_profile, "com.thetypefounders/check/features_default_languagesystem"
+    )
+
+    ufo, _ = empty_ufo_font
+
+    ufo.features.text = (
+        "languagesystem latn dflt; feature liga { sub f i by f_i; } liga;"
+    )
+
+    assert_results_contain(check(ufo), WARN, "default-languagesystem")
+
+
+def test_check_default_languagesystem_pass_with_default_languagesystem(empty_ufo_font):
+    """Pass if `languagesystem DFLT dflt` is explicitly used in the features."""
+    check = CheckTester(
+        ufo_sources_profile, "com.thetypefounders/check/features_default_languagesystem"
+    )
+
+    ufo, _ = empty_ufo_font
+
+    ufo.features.text = """languagesystem DFLT dflt;
+languagesystem latn dflt;
+feature liga { sub f i by f_i; } liga;"""
+
+    assert_PASS(check(ufo))