The AAT specification defines the following "feature" codes.
kAllTypographicFeatures
All Typographic FeatureskLigatures
Ligatures (non-exclusive set)kRequiredLigaturesOnSelector
Required LigatureskCommonLigaturesOnSelector
Common LigatureskRareLigaturesOnSelector
Rare LigatureskLogosOnSelector
Logos, deprecatedkRebusPicturesOnSelector
Rebus PictureskDiphthongLigaturesOnSelector
Diphthong LigatureskSquaredLigaturesOnSelector
Squared LigatureskAbbrevSquaredLigaturesOnSelector
Squared Ligatures, AbbreviatedkSymbolLigaturesOnSelector
Symbol LigatureskContextualLigaturesOnSelector
Contextual LigatureskHistoricalLigaturesOnSelector
Historical LigatureskCursiveConnection
Cursive Connection (non-exclusive set)kUnconnectedSelector
UnconnectedkPartiallyConnectedSelector
Partially ConnectedkCursiveSelector
CursivekLetterCase
Letter Case (non-exclusive set), deprecatedkUpperAndLowerCaseSelector
Upper & Lower Case, deprecatedkAllCapsSelecto
rAll Caps, deprecatedkAllLowerCaseSelecto
rAll Lower Case, deprecatedkSmallCapsSelector
Small Caps, deprecatedkInitialCapsSelector
Initial Caps, deprecatedkInitialCapsAndSmallCapsSelector
Initial Caps and Small Caps, deprecatedkVerticalSubstitution
Vertical SubstitutionkLinguisticRearrangement
Linguistic RearrangementkNumberSpacing
Number Spacing (non-exclusive set)kMonospacedNumbersSelector
Monospaced NumberskProportionalNumbersSelector
Proportional NumberskThirdWidthNumbersSelector
Third-width NumeralskQuarterWidthNumbersSelector
Quarter-width NumeralskSmartSwash
Smart Swashes (non-exclusive set)kWordInitialSwashesOnSelector
Word Initial SwasheskWordFinalSwashesOnSelector
Word Final SwasheskLineInitialSwashesOnSelector
Line Initial Swashes, deprecatedkLineFinalSwashesOnSelector
Line Final Swashes, deprecatedkNonFinalSwashesOnSelector
Non-Final SwasheskDiacritics
Diacritics (non-exclusive set)kShowDiacriticsSelector
Show DiacriticskHideDiacriticsSelector
Hide DiacriticskDecomposeDiacriticsSelector
Decompose DiacriticskVerticalPosition
Vertical Position (non-exclusive set)kFractions
Fractions (non-exclusive set)kNoFractionsSelector
No FractionskVerticalFractionsSelector
Vertical FractionskDiagonalFractionsSelector
Diagonal FractionskOverlappingCharacters
Overlapping CharacterskTypographicExtras
Typographic Extras (non-exclusive set)kHyphensToEmDashOnSelector
Hyphens to Em Dash, deprecatedkHyphenToEnDashOnSelector
Hyphen to En Dash, deprecatedkSlashedZeroOnSelector
Unslashed ZerokFormInterrobangOnSelector
Form Interrobang, deprecatedkSmartQuotesOnSelector
Smart Quotes, deprecatedkPeriodsToEllipsisOnSelector
Periods to Ellipsis, deprecatedkMathematicalExtras
Mathematical Extras (non-exclusive set)kHyphenToMinusOnSelector
Hyphen To Minus, deprecatedkAsteriskToMultiplyOnSelector
Asterisk to Multiply, deprecatedkSlashToDivideOnSelector
Slash to Divide, deprecatedkInequalityLigaturesOnSelector
Inequality Ligatures, deprecatedkExponentsOnSelector
Exponents, deprecatedkMathematicalGreekOnSelector
Mathematical GreekkOrnamentSets
Ornament Sets (non-exclusive set)kNoOrnamentsSelector
NonekDingbatsSelector
DingbatskPiCharactersSelector
Pi CharacterskFleuronsSelector
FleuronskDecorativeBordersSelector
Decorative BorderskInternationalSymbolsSelector
International SymbolskMathSymbolsSelector
Math SymbolskCharacterAlternatives
Character AlternativeskDesignComplexity
Design Complexity (non-exclusive set)kDesignLevel1Selector
Design Level 1kDesignLevel2Selector
Design Level 2kDesignLevel3Selector
Design Level 3kDesignLevel4Selector
Design Level 4kDesignLevel5Selector
Design Level 5kStyleOptions
Style Options (non-exclusive set)kNoStyleOptionsSelector
No Style OptionskDisplayTextSelector
Display TextkEngravedTextSelector
Engraved TextkIlluminatedCapsSelector
Illuminated CapskTitlingCapsSelector
Titling CapskTallCapsSelector
Tall CapskCharacterShape
Character Shape (non-exclusive set)kTraditionalCharactersSelector
Traditional GlyphskSimplifiedCharactersSelector
Simplified GlyphskJIS1978CharactersSelector
JIS 1978 GlyphskJIS1983CharactersSelector
JIS 1983 GlyphskJIS1990CharactersSelector
JIS 1990 GlyphskTraditionalAltOneSelector
Traditional Glyphs, Alternative Set 1kTraditionalAltTwoSelector
Traditional Glyphs, Alternative Set 2kTraditionalAltThreeSelector
Traditional Glyphs, Alternative Set 3kTraditionalAltFourSelector
Traditional Glyphs, Alternative Set 4kTraditionalAltFiveSelector
Traditional Glyphs, Alternative Set 5kExpertCharactersSelector
Expert GlyphskJIS2004CharactersSelector
JIS 2004 GlyphskHojoCharactersSelector
Hojo GlyphskNLCCharactersSelector
NLC GlyphskTraditionalNamesCharactersSelector
Traditional NameskNumberCase
Number Case (non-exclusive set)kLowerCaseNumbersSelector
Lower Case NumberskUpperCaseNumbersSelector
Upper Case NumberskTextSpacing
Text Spacing (non-exclusive set)kProportionalTextSelector
ProportionalkMonospacedTextSelector
MonospacekHalfWidthTextSelector
Half-widthkThirdWidthTextSelector
Third-widthkQuarterWidthTextSelector
Quarter-widthkAltProportionalTextSelector
Alternate ProportionalkAltHalfWidthTextSelector
Alternate Half-widthkTransliteration
Transliteration (non-exclusive set)kNoTransliterationSelector
No TransliterationkHanjaToHangulSelector
Hanja to Hangul, deprecatedkHiraganaToKatakanaSelector
Hiragana To Katakana, deprecatedkKatakanaToHiraganaSelector
Katakana To Hiragana, deprecatedkKanaToRomanizationSelector
Kana To Romanization, deprecatedkRomanizationToHiraganaSelector
Romanization To Hiragana, deprecatedkRomanizationToKatakanaSelector
Romanization To Katakana, deprecatedkHanjaToHangulAltOneSelector
Hanja To Hangul Alt One, deprecatedkHanjaToHangulAltTwoSelector
Hanja To Hangul Alt Two, deprecatedkHanjaToHangulAltThreeSelector
Hanja To Hangul Alt Three, deprecatedkAnnotation
Annotation (non-exclusive set)kNoAnnotationSelector
No AnnotationkBoxAnnotationSelector
Box AnnotationkRoundedBoxAnnotationSelector
Rounded Box AnnotationkCircleAnnotationSelector
Circle AnnotationkInvertedCircleAnnotationSelector
Inverted Circle AnnotationkParenthesisAnnotationSelector
Parenthesis AnnotationkPeriodAnnotationSelector
Period AnnotationkRomanNumeralAnnotationSelector
Roman Numeral AnnotationkDiamondAnnotationSelector
Diamond AnnotationkInvertedBoxAnnotationSelector
Inverted Box AnnotationkInvertedRoundedBoxAnnotationSelector
Inverted Rounded Box AnnotationkKanaSpacing
Kana Spacing (non-exclusive set)kFullWidthKanaSelector
Full WidthkProportionalKanaSelector
ProportionalkIdeographicSpacing
Ideographic SpacingkFullWidthIdeographsSelector
Full WidthkProportionalIdeographsSelector
ProportionalkHalfWidthIdeographsSelector
Half Width- kUnicodeDecomposition` Unicode Decomposition
kCanonicalCompositionOnSelector
Canonical CompositionkCompatibilityCompositionOnSelector
Compatibility CompositionkTranscodingCompositionOnSelector
Transcoding CompositionkRubyKana
Ruby Kana (non-exclusive set)kNoRubyKanaSelector
No Ruby Kana, deprecatedkRubyKanaSelector
Ruby Kana, deprecatedkRubyKanaOnSelector
Ruby KanakCJKSymbolAlternatives
CJK Symbol Alternatives (non-exclusive set)kNoCJKSymbolAlternativesSelector
No CJK Symbol AlternativeskCJKSymbolAltOneSelector
CJK Symbol Alt OnekCJKSymbolAltTwoSelector
CJK Symbol Alt TwokCJKSymbolAltThreeSelector
CJK Symbol Alt ThreekCJKSymbolAltFourSelector
CJK Symbol Alt FourkCJKSymbolAltFiveSelector
CJK Symbol Alt FivekIdeographicAlternatives
Ideographic Alternatives (non-exclusive set)kNoIdeographicAlternativesSelector
No Ideographic AlternativeskIdeographicAltOneSelector
Ideographic Alt OnekIdeographicAltTwoSelector
Ideographic Alt TwokIdeographicAltThreeSelector
Ideographic Alt ThreekIdeographicAltFourSelector
Ideographic Alt FourkIdeographicAltFiveSelector
Ideographic Alt FivekCJKVerticalRomanPlacement
CJK Vertical Roman Placement (non-exclusive set)kCJKVerticalRomanCenteredSelector
CJK Vertical Roman CenteredkCJKVerticalRomanHBaselineSelector
CJK Vertical Roman H BaselinekItalicCJKRoman
Italic CJK Roman (non-exclusive set)kNoCJKItalicRomanSelector
No CJK Italic Roman, deprecatedkCJKItalicRomanSelector
CJK Italic Roman, deprecatedkCJKItalicRomanOnSelector
CJK Italic RomankCaseSensitiveLayout
(non-exclusive set)kCaseSensitiveLayoutOnSelector
Case Sensitive LayoutkCaseSensitiveSpacingOnSelector
Case Sensitive SpacingkAlternateKana
Alternate Kana (non-exclusive set)kAlternateHorizKanaOnSelector
Alternate Horizontal KanakAlternateVertKanaOnSelector
Alternate Vertical KanakStylisticAlternatives
Stylistic Alternatives (non-exclusive set)kNoStylisticAlternatesSelector
No Stylistic AlternateskStylisticAltOneOnSelector
Stylistic Alt OnekStylisticAltTwoOnSelector
Stylistic Alt TwokStylisticAltThreeOnSelector
Stylistic Alt ThreekStylisticAltFourOnSelector
Stylistic Alt FourkStylisticAltFiveOnSelector
Stylistic Alt FivekStylisticAltSixOnSelector
Stylistic Alt SixkStylisticAltSevenOnSelector
Stylistic Alt SevenkStylisticAltEightOnSelector
Stylistic Alt EightkStylisticAltNineOnSelector
Stylistic Alt NinekStylisticAltTenOnSelector
Stylistic Alt TenkStylisticAltElevenOnSelector
Stylistic Alt ElevenkStylisticAltTwelveOnSelector
Stylistic Alt TwelvekStylisticAltThirteenOnSelector
Stylistic Alt ThirteenkStylisticAltFourteenOnSelector
Stylistic Alt FourteenkStylisticAltFifteenOnSelector
Stylistic Alt FifteenkStylisticAltSixteenOnSelector
Stylistic Alt SixteenkStylisticAltSeventeenOnSelector
Stylistic Alt SeventeenkStylisticAltEighteenOnSelector
Stylistic Alt EighteenkStylisticAltNineteenOnSelector
Stylistic Alt NineteenkStylisticAltTwentyOnSelector
Stylistic Alt TwentykContextualAlternates
Contextual Alternates (non-exclusive set)kContextualAlternatesOnSelector
Contextual AlternateskSwashAlternatesOnSelector
Swash AlternateskContextualSwashAlternatesOnSelector
Contextual Swash AlternateskLowerCase
Lower Case (non-exclusive set)kDefaultLowerCaseSelector
Default Lower CasekLowerCaseSmallCapsSelector
Lower Case Small CapskLowerCasePetiteCapsSelector
Lower Case Petite CapskUpperCase
Upper Case (non-exclusive set)kDefaultUpperCaseSelector
Default Upper CasekUpperCaseSmallCapsSelector
Upper Case Small CapskUpperCasePetiteCapsSelector
Upper Case Petite CapskLanguageTag
Language TagkCJKRomanSpacing
CJK Roman SpacingkHalfWidthCJKRomanSelector
Half-widthkProportionalCJKRomanSelector
ProportionalkDefaultCJKRomanSelector
Default RomankFullWidthCJKRomanSelector
Full-width Roman