Disambiguate modeline character for UTF-8?

[Ulrich Mueller]

Presumably UTF-8 is the most popular coding system today. Nevertheless,
it shares its mnemonic character displayed in the modeline with several
others (while legacy codings like ISO-8859-1 have their unique char):

   U -- utf-8*  (all variants)
   U -- utf-16* (all variants)
   U -- utf-7
   u -- utf-7-imap
   U -- koi8-u

I wonder if this could be disambiguated, such that "U" would be used
exclusively for UTF-8 and its variants. For example, as follows:

   U -- utf-8*  (all variants)
   u -- utf-16* (all variants)
   m -- utf-7*  (Mnemonic: "m" for mail-safe or MIME)
   Y -- koi8-u  (Mnemonic: "Y" looks similar to 1st letter in "Українська")

WDYT?