magic-fallback-mode-alist

magic-fallback-mode-alist is a variable defined in `files.el'.
Its value is shown below.

• This variable may be risky if used as a file-local variable.

Documentation:
Like `magic-mode-alist' but has lower priority than `auto-mode-alist'.
Each element looks like (REGEXP . FUNCTION) or (MATCH-FUNCTION . FUNCTION).
After visiting a file, if REGEXP matches the text at the beginning of the
buffer, or calling MATCH-FUNCTION returns non-nil, `normal-mode' will
call FUNCTION, provided that `magic-mode-alist' and `auto-mode-alist'
have not specified a mode for this file.

If FUNCTION is nil, then it is not called.

Value:

((image-type-auto-detected-p . image-mode)
 ("\\(PK00\\)?[P]K" . archive-mode)
 ("\\(?:<\\?xml[ 	
\n]+[^>]*>\\)?[ 	
\n]*<\\(?:!--\\(?:[^-]\\|-[^-]\\)*-->[ 	
\n]*<\\)*\\(?:!DOCTYPE[ 	
\n]+[^>]*>[ 	
\n]*<[ 	
\n]*\\(?:!--\\(?:[^-]\\|-[^-]\\)*-->[ 	
\n]*<\\)*\\)?[Hh][Tt][Mm][Ll]" . html-mode)
 ("[ 	
\n]*<\\)*!DOCTYPE " . sgml-mode)
 ("%!PS" . ps-mode)
 ("# xmcd " . conf-unix-mode))