"Globs" are the patterns you type when you do stuff like ls *.js on
the command line, or put build/* in a .gitignore file.
Before parsing the path part patterns, braced sections are expanded
into a set. Braced sections start with { and end with }, with any
number of comma-delimited sections within. Braced sections may contain
slash characters, so a{/b/c,bcd} would expand into a/b/c and abcd.