https://gitlab.synchro.net/main/sbbs/-/commit/1917099ba9f7dabd7940a2a7fd8de7dff1929aed#note_4745
backslash() is for appending a slash or backslash on the end of a string when you're going to possibly pass that string onto an OS path interpreter (e.g. command.com, cmd.exe) where it then matters if it's a backward or forward slash (on Windows).
backslash() is not deprecated is sometimes necessary, like I said, when you're passing the resulting string on to an external program.
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