f a/b.js   !**/*.md
f a.js     !**/*.md
f a/b.md   !**/*.md
f a.md     !**/*.md

f a/b.js    !*.md
f a.js      !*.md
f a/b.md    !*.md
f a.md      !*.md

f a.js      !**/*.md
f b.md      !**/*.md
f c.txt     !**/*.md