v0.24.0

fxcss 0.24.0 works with Firefox 159, which is in Beta now and due for release on 6 November. It also stops reporting a browser that failed to start as a problem with your theme.

• Firefox 159 support. Firefox 159 only lets automation reach the browser's own UI when Firefox is started with MOZ_REMOTE_ALLOW_SYSTEM_ACCESS=1. Without it, every fxcss command failed on Beta and Nightly with "System access is required". fxcss now sets the variable for the Firefox it launches; older versions ignore it. Upgrade before 6 November, or capture, audit and preview workflows will start failing on release Firefox.
• fxcss audit exits 2 when it cannot run, for example when Firefox fails to start, and prints a one-line error instead of a traceback. Exit status 1 still means the audit ran and found something.
• --strict-vars now works together with --no-unused. Before, combining them silently skipped the custom-property check. When --no-unused hides the full report, the failure lists each property and where it is set.
• The generated Firefox watch workflow reads the Firefox version without starting a browser. It opens a "needs attention" issue only for real audit findings, and fails the run when Firefox could not be audited or captured. Before, those runs finished green and filed misleading selector issues.
• CI tests the Python 3.9 minimum on Ubuntu 24.04, because ubuntu-latest (now 26.04) has no Python 3.9.

Upgrade an existing installation with pipx upgrade fxcss, or use pip install "fxcss[images]==0.24.0" in a virtual environment or CI.

Generated workflows keep their version pins until you regenerate them. Run fxcss init with your existing options and --force, then review the diff to keep local edits. Your theme's workflows need 0.24.0 before Firefox 159 reaches release. A watch that passes --strict-vars may now report custom-property overrides that no longer do anything; it has been asking for that check all along.

Full changes since v0.23.0.

The release workflow passed all 26 jobs, including cross-platform browser tests, installed-package checks and the PyPI installability gate. Before tagging, a Firefox compatibility run on the release commit passed on Stable, ESR, Beta and Nightly. That was the first clean Beta and Nightly result since 28 September.

A fresh installation from PyPI showed version 0.24.0. With a theme folder that does not exist, it reported "audit could not complete" with exit status 2 and no traceback. The published wheel and source archive have the same SHA256 hashes as the files the release workflow built and tested.