Really weird and convoluted reasons for it. A better question is why it was never fixed / renamed to proper names.
There's a field in the Volume Boot Record of disc volumes, in the PC compatible world, that was supposed to be the name of the OEM whose software formatted the volume. It was (and is) a few bytes of identifying human-readable text. Operating systems ended up doing string comparisons and parsing numbers, and breaking in odd ways, including not even recognizing their own handiwork, when operating system vendors did not use the name of the first vendor.
* https://jdebp.uk/FGA/volume-boot-block-oem-name-field.html
It has probably been long enough since MS-DOS 3.3 and in turn the Browser Wars that someone is right now failing to learn from history and making this mistake anew, yet again, somewhere.