Release 2.6 (2022-01-24)

The Nix CLI now searches for a flake.nix up until the root of the current Git repository or a filesystem boundary rather than just in the current directory.
The TOML parser used by builtins.fromTOML has been replaced by a more compliant one.
Added :st/:show-trace commands to nix repl, which are used to set or toggle display of error traces.
New builtin function builtins.zipAttrsWith with the same functionality as lib.zipAttrsWith from Nixpkgs, but much more efficient.
New command nix store copy-log to copy build logs from one store to another.
The commit-lockfile-summary option can be set to a non-empty string to override the commit summary used when committing an updated lockfile. This may be used in conjunction with the nixConfig attribute in flake.nix to better conform to repository conventions.
docker run -ti nixos/nix:master will place you in the Docker container with the latest version of Nix from the master branch.