doc/manual/source/release-notes/rl-2.14.md
A new function builtins.readFileType is available. It is similar to
builtins.readDir but acts on a single file or directory.
In flakes, the .outPath attribute of a flake now always refers to
the directory containing the flake.nix. This was not the case for
when flake.nix was in a subdirectory of e.g. a Git repository.
The root of the source of a flake in a subdirectory is still
available in .sourceInfo.outPath.
In derivations that use structured attributes, you can now use unsafeDiscardReferences
to disable scanning a given output for runtime dependencies:
__structuredAttrs = true;
unsafeDiscardReferences.out = true;
This is useful e.g. when generating self-contained filesystem images with their own embedded Nix store: hashes found inside such an image refer to the embedded store and not to the host's Nix store.
This requires the discard-references experimental feature.