[File] Meaning of regex/T?

[Sudarshan S Chawathe]

There are a few instances of regex/T in the collection in magic/Magdir
(1 in the file windows and 2 in msdos) but I don't think that flag is
documented in 'man magic', which only mentions flags c, s, and l for
regex.

Does /T for regex mean something similar to its meaning for the string
type (i.e., trim)?  In that case, does it mean that the string matching
the given regex is trimmed before printing?

Related: are the flags for the regex type case-insensitive?  In
particular, is regex/C an acceptable alternative for regex/c?  If not,
what does regex/C mean?  (For instance, the file msdos contains
regex/512/C.)

Regards,

-chaw