Choose one answer. All questions are included, with explanations after checking. No time limit. Training target: 21/26. Trace and debug glyph substitutions in explicitly specified Latin left-to-right runs: marked input, backtrack and lookahead, ordered classes, lookup stages, exceptions, nested actions, length changes, mark filtering and activation. Uses OpenType 1.9.1 and current Adobe FEA syntax. Excludes a complete shaping-engine implementation, complex-script reordering, GPOS, variable-font FeatureVariations and font-editor certification. Sources: https://learn.microsoft.com/en-us/typography/opentype/spec/gsub https://learn.microsoft.com/en-us/typography/opentype/spec/chapter2 https://adobe-type-tools.github.io/afdko/OpenTypeFeatureFileSpecification.html
