diff --git a/css/properties/font-language-override.json b/css/properties/font-language-override.json
new file mode 100644
index 00000000000000..470442d87b5324
--- /dev/null
+++ b/css/properties/font-language-override.json
@@ -0,0 +1,87 @@
+{
+  "css": {
+    "properties": {
+      "font-language-override": {
+        "__compat": {
+          "mdn_url": "https://developer.mozilla.org/docs/Web/CSS/font-language-override",
+          "support": {
+            "webview_android": {
+              "version_added": false
+            },
+            "chrome": {
+              "version_added": false
+            },
+            "chrome_android": {
+              "version_added": false
+            },
+            "edge": {
+              "version_added": false
+            },
+            "edge_mobile": {
+              "version_added": false
+            },
+            "firefox": [
+              {
+                "version_added": "34"
+              },
+              {
+                "version_added": "24",
+                "version_removed": "34",
+                "flag": {
+                  "type": "preference",
+                  "name": "layout.css.font-features.enabled",
+                  "value_to_set": "true"
+                }
+              },
+              {
+                "prefix": "-moz-",
+                "version_added": "4"
+              }
+            ],
+            "firefox_android": [
+              {
+                "version_added": "34"
+              },
+              {
+                "version_added": "24",
+                "version_removed": "34",
+                "flag": {
+                  "type": "preference",
+                  "name": "layout.css.font-features.enabled",
+                  "value_to_set": "true"
+                }
+              },
+              {
+                "prefix": "-moz-",
+                "version_added": "4"
+              }
+            ],
+            "ie": {
+              "version_added": false
+            },
+            "ie_mobile": {
+              "version_added": false
+            },
+            "opera": {
+              "version_added": false
+            },
+            "opera_android": {
+              "version_added": false
+            },
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": {
+              "version_added": false
+            }
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      }
+    }
+  }
+}
diff --git a/css/properties/font-size-adjust.json b/css/properties/font-size-adjust.json
new file mode 100644
index 00000000000000..7995c40591b38d
--- /dev/null
+++ b/css/properties/font-size-adjust.json
@@ -0,0 +1,72 @@
+{
+  "css": {
+    "properties": {
+      "font-size-adjust": {
+        "__compat": {
+          "mdn_url": "https://developer.mozilla.org/docs/Web/CSS/font-size-adjust",
+          "support": {
+            "webview_android": {
+              "version_added": null
+            },
+            "chrome": {
+              "version_added": "43",
+              "flag": {
+                "type": "preference",
+                "name": "Enable experimental Web Platform features"
+              }
+            },
+            "chrome_android": {
+              "version_added": null
+            },
+            "edge": {
+              "version_added": false
+            },
+            "edge_mobile": {
+              "version_added": false
+            },
+            "firefox": [
+              {
+                "version_added": "3",
+                "notes": "Before Firefox 40, <code>font-size-adjust: 0</code> was incorrectly interpreted as <code>font-size-adjust: none</code> (<a href='https://bugzil.la/1144885'>bug 1144885</a>)."
+              },
+              {
+                "version_added": "1",
+                "notes": "Before Firefox 3, <code>font-size-adjust</code> was supported on Windows only."
+              }
+            ],
+            "firefox_android": {
+              "version_added": "4"
+            },
+            "ie": {
+              "version_added": false
+            },
+            "ie_mobile": {
+              "version_added": null
+            },
+            "opera": {
+              "version_added": "30",
+              "flag": {
+                "type": "preference",
+                "name": "Enable experimental Web Platform features"
+              }
+            },
+            "opera_android": {
+              "version_added": null
+            },
+            "safari": {
+              "version_added": false
+            },
+            "safari_ios": {
+              "version_added": null
+            }
+          },
+          "status": {
+            "experimental": false,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      }
+    }
+  }
+}
diff --git a/css/properties/font-size.json b/css/properties/font-size.json
new file mode 100644
index 00000000000000..123187b49f24e3
--- /dev/null
+++ b/css/properties/font-size.json
@@ -0,0 +1,114 @@
+{
+  "css": {
+    "properties": {
+      "font-size": {
+        "__compat": {
+          "mdn_url": "https://developer.mozilla.org/docs/Web/CSS/font-size",
+          "support": {
+            "webview_android": {
+              "version_added": "1"
+            },
+            "chrome": {
+              "version_added": "1"
+            },
+            "chrome_android": {
+              "version_added": "1"
+            },
+            "edge": {
+              "version_added": "12"
+            },
+            "edge_mobile": {
+              "version_added": "12"
+            },
+            "firefox": {
+              "version_added": "1"
+            },
+            "firefox_android": {
+              "version_added": "4"
+            },
+            "ie": {
+              "version_added": "5.5"
+            },
+            "ie_mobile": {
+              "version_added": "6"
+            },
+            "opera": {
+              "version_added": "7"
+            },
+            "opera_android": {
+              "version_added": "6"
+            },
+            "safari": {
+              "version_added": "1"
+            },
+            "safari_ios": {
+              "version_added": "1"
+            }
+          },
+          "status": {
+            "experimental": false,
+            "standard_track": true,
+            "deprecated": false
+          }
+        },
+        "rem_values": {
+          "__compat": {
+            "description": "Rem values",
+            "support": {
+              "webview_android": {
+                "version_added": "4.1"
+              },
+              "chrome": {
+                "version_added": "31"
+              },
+              "chrome_android": {
+                "version_added": "42"
+              },
+              "edge": {
+                "version_added": "12"
+              },
+              "edge_mobile": {
+                "version_added": "12"
+              },
+              "firefox": {
+                "version_added": "31",
+                "notes": [
+                  "Before Firefox 57, animations using em units are not affected by changes to the <code>font-size</code> of the animated element's parent (<a href='https://bugzil.la/1254424'>bug 1254424</a>).",
+                  "Before Firefox 57, some language settings' inherited <code>font-size</code> is smaller than expected (<a href='https://bugzil.la/1391341'>bug 1391341</a>)."
+                ]
+              },
+              "firefox_android": {
+                "version_added": "31"
+              },
+              "ie": [
+                {
+                  "version_added": "11"
+                },
+                {
+                  "partial_implementation": true,
+                  "version_added": "9",
+                  "version_removed": "10"
+                }
+              ],
+              "ie_mobile": {
+                "version_added": "10"
+              },
+              "opera": {
+                "version_added": "28"
+              },
+              "opera_android": {
+                "version_added": "12"
+              },
+              "safari": {
+                "version_added": "7"
+              },
+              "safari_ios": {
+                "version_added": true
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+}
diff --git a/css/properties/font-stretch.json b/css/properties/font-stretch.json
new file mode 100644
index 00000000000000..67d763bfbe59ef
--- /dev/null
+++ b/css/properties/font-stretch.json
@@ -0,0 +1,57 @@
+{
+  "css": {
+    "properties": {
+      "font-stretch": {
+        "__compat": {
+          "mdn_url": "https://developer.mozilla.org/docs/Web/CSS/font-stretch",
+          "support": {
+            "webview_android": {
+              "version_added": false
+            },
+            "chrome": {
+              "version_added": "48"
+            },
+            "chrome_android": {
+              "version_added": null
+            },
+            "edge": {
+              "version_added": "12"
+            },
+            "edge_mobile": {
+              "version_added": "12"
+            },
+            "firefox": {
+              "version_added": "9"
+            },
+            "firefox_android": {
+              "version_added": "9"
+            },
+            "ie": {
+              "version_added": "9"
+            },
+            "ie_mobile": {
+              "version_added": null
+            },
+            "opera": {
+              "version_added": "35"
+            },
+            "opera_android": {
+              "version_added": false
+            },
+            "safari": {
+              "version_added": "11"
+            },
+            "safari_ios": {
+              "version_added": null
+            }
+          },
+          "status": {
+            "experimental": false,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      }
+    }
+  }
+}
diff --git a/css/properties/font-style.json b/css/properties/font-style.json
new file mode 100644
index 00000000000000..778cfc440fc9cc
--- /dev/null
+++ b/css/properties/font-style.json
@@ -0,0 +1,59 @@
+{
+  "css": {
+    "properties": {
+      "font-style": {
+        "__compat": {
+          "mdn_url": "https://developer.mozilla.org/docs/Web/CSS/font-style",
+          "support": {
+            "webview_android": {
+              "version_added": "1"
+            },
+            "chrome": {
+              "version_added": "1"
+            },
+            "chrome_android": {
+              "version_added": "1"
+            },
+            "edge": {
+              "version_added": "12"
+            },
+            "edge_mobile": {
+              "version_added": "12"
+            },
+            "firefox": {
+              "version_added": "1",
+              "notes": "Before Firefox 44, <code>oblique</code> was not distinguished from <code>italic</code>."
+            },
+            "firefox_android": {
+              "version_added": "4",
+              "notes": "Before Firefox 44, <code>oblique</code> was not distinguished from <code>italic</code>."
+            },
+            "ie": {
+              "version_added": "4"
+            },
+            "ie_mobile": {
+              "version_added": "6"
+            },
+            "opera": {
+              "version_added": "7"
+            },
+            "opera_android": {
+              "version_added": "6"
+            },
+            "safari": {
+              "version_added": "1"
+            },
+            "safari_ios": {
+              "version_added": "1"
+            }
+          },
+          "status": {
+            "experimental": false,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      }
+    }
+  }
+}