The staging cycle has been somewhat wonky this time due to a lot of breaking changes, but it has been merged to master, and nixos-unstable will update when the builds are done. You can keep an eye out on https://hydra.nixos.org/eval/1789263#tabs-unfinished .
Search isn’t literally searching the git repo–it’s an index that has to be updated. This means there’ll always be at least a little lag time between updates to the repo and what’s available in search.
The nixos-unstable channel finally got bumped after 3 days of build failures (see https://status.nixos.org).
The package index should get updated soon to reflect this.