There are two answers saying that, and one is sourced to Wikipedia whilst the other has screenshots of tests being run. Just copying Wikipedia to Stack Exchang

There are two answers saying that, and one is sourced to Wikipedia whilst the other has screenshots of tests being run. Just copying Wikipedia to Stack Exchange isn't a good idea in general. In any case, there are plenty of contemporary 1980s discussions of SWITCHAR in CONFIG.SYS to be had, that go over the pathname separator characters as well. This has been well-known as a semi-official thing for 4 decades. Heck, one could even cite Peter Norton on the pathname separators, writing the The dissection of DOS 3.0 article in his column in the 1984-10-30 edition (volume 3 number 21) of PC magazine.