-For compatibility with this program, source filenames should conform to
- the following rules :—
-
-- They should not start with a hyphen‐minus.
- This is to prevent confusion between filenames and options on the
- commandline.
-
-- They should not contain spaces, colons, percent signs, backticks,
- question marks, hashes, or backslashes.
-
-In general, filenames should be such that they do not require
- percent‐encoding in the path component of an i·r·i.
+For compatibility with this program, source filenames should not
+ contain Ascii whitespace or any of the following Ascii characters:
+ ``!"#$%&()-:<>?\^`{|}``.
+These characters are either invalid in u·r·i’s or conflict with aspects
+ of the Make or commandline syntax.