They don't necessarily fit the definition of "arcane", but there's certainly specialized knowledge that at this point exists primarily on the Internet Archive.

They don't necessarily fit the definition of "arcane", but there's certainly specialized knowledge that at this point exists primarily on the Internet Archive. At this point in time, there have been lots of niche websites and forums and many have shut down. In some cases, those websites housed actual practical knowledge. Example: I drive a Mazdaspeed3. There was a forum dedicated (partly) to that car, and it went down. Now that it's gone, a lot of information on how to work on it is also gone or much more difficult to come by.