PML files are not required to have particular file extensions. PML2 Functions, Objects, Forms and Macros are normally stored in files with the extensions .pmlfnc, .pmlobj, .pmlfrm and .pmlmac respectively, but other PML files, such as those in the PMLUI folder of an installation have no extension at all, and a PML file with any extension may be read with a $m command.