hi-lock-file-patterns-policy

hi-lock-file-patterns-policy is a variable defined in `hi-lock.el'.
Its value is

ask

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

Documentation:
Specify when hi-lock should use patterns found in file.
If `ask', prompt when patterns found in buffer; if bound to a function,
use patterns when function returns t (function is called with patterns
as first argument); if nil or `never' or anything else, don't use file
patterns.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 22.1 of Emacs.