alt Hacker NewsWhich is especially odd because the author (Sam Hughes) lives in the UK and wrote the original in UK English, but apparently wrote the rewrite in US English. For example, a chapter in the original was titled "Case Colourless Green", but in the US edition of the rewrite that chapter is "Case Colorless Green" (without the 'u'). So Hughes, a native UK English speaker, wrote the rewrite in a non-native (to him) dialect, then had it (lazily) translated into his native dialect.
It was probably to deal with the transposition [0] out of the SCP universe into a new one. SCP is vaguely 'set' in the US because that's how a majority of the contributors naturally write and spell things, which sets the voice of the world indirectly.
[0] AKA "filing the serial numbers off" when it's explicitly fanfiction instead of a shared universe model like SCP