Short answers, pulled from the story.
Ogg is derived from "ogging," a term from the computer game Netrek meaning doing something forcefully, possibly without regard for future resource costs. The project's authors felt the name reflected their ambition given the limited hardware of the time.
Ogg is maintained by the Xiph.Org Foundation. The reference implementation, libogg, is released under the New BSD License and was at version 1.3.3 as of the 7th of November, 2017.
The most common audio codecs for Ogg are Vorbis, which handles general audio at roughly 16-500 kilobits per second per channel, and its successor Opus, which covers voice and music at approximately 6-510 kilobits per second per channel. Lossless options include FLAC and OggPCM.
Since 2007, Xiph.Org recommends .ogg only for Ogg Vorbis audio files. The extension .oga is used for audio-only files, .ogv for video with or without sound, and .ogx for multiplexed Ogg content.
OGM was a 2002 workaround that embedded Microsoft DirectShow video inside an Ogg-based wrapper. It is no longer developed or supported and is formally discouraged by Xiph.Org, which later introduced the official .ogv extension for Ogg video.
Vorbis is named after a character in Terry Pratchett's novel Small Gods. The connection to Pratchett is indirect: the Ogg name itself is unrelated to Nanny Ogg from the Discworld novels, but the Vorbis codec was deliberately named after a Pratchett character.