This specific archive typically contains the "scene" release update by the group (or related repackers). It is used to bring a base installation of the Anniversary Edition up to the 1.6.323 build, which was a significant early patch for the AE release.
: Patches for bugs introduced in the initial Anniversary Edition rollout. sc18069-TESVSAEUpd1632308.rar
This specific version (1.6.323) is often sought by players who want to "freeze" their game at a certain point to maintain compatibility with specific mods before later updates (like 1.6.640 or 1.6.1130) broke various plugins. This specific archive typically contains the "scene" release
: Updated SkyrimSE.exe and SkyrimSELauncher.exe files. sc18069-TESVSAEUpd1632308.rar
: Updates to the underlying framework that handles the "Anniversary Upgrade" content (the 74+ Creation Club mods included in AE).