You can include wildcards in extensions. Use a question
mark (?) to represent a single character and an asterisk (*) to
represent two or more characters. See the following examples:
*.*m
matches the following files: ABC.dem, ABC.prm, ABC.sdcm
*.m*r
matches the following files: ABC.mgdr, ABC.mtp2r, ABC.mdmr
*.fm?
matches the following files: ABC.fme, ABC.fml, ABC.fmp