It’s basically just configuration data for MS-DOS apps running under Windows (or some over MS-DOS multitaskers). Stuff like EMS and XMS memory amounts, various

It’s basically just configuration data for MS-DOS apps running under Windows (or some over MS-DOS multitaskers). Stuff like EMS and XMS memory amounts, various config options etc. Fun fact: under the hood, PIF files are sent to the same ShellExecute function as EXEs, and if you have an EXE with a PIF extension, it runs the EXE code as normal. Funnier fact: In Windows 95 and onwards, the UI presents PIFs as a special case of shortcuts, and as with LNK files, Windows always hides (hid?) the extension, even if you have “always show extensions” on. When I get home, I’ll have to check if Windows 11 still has this behaviour… Edit: Yeah, creating a copy of calc.exe in my ~/Documents folder and renaming it calc.docx.pif does result in a working calculator file that presents gives its name as "calc.docx", albeit with a "shortcut to generic file" icon and a type of "Shortcut to MS-DOS Program" despite the fact that I can't think of any legitimate reason to do anything with a real PIF file on Windows 11 (24H2).