Means URLs like :/icons/foo.jpg should become icons:foo.jpg
This is part of the prep work for a PyQt6 update. PyQt6 has dropped
pyrcc, so we can longer generate the icons_qrc.py file we did previously.
Qt Designer expects us to use the resource system, so we continue to
generate the icons.qrc file to make editing the UI files easier. But at
runtime, we no longer use that file.
This adds Python 3.9 and 3.10 typing syntax to files that import
attributions from __future___. Python 3.9 should be able to cope with
the 3.10 syntax, but Python 3.8 will no longer work.
On Windows/Mac, install the latest Python 3.9 version from python.org.
There are currently no orjson wheels for Python 3.10 on Windows/Mac,
which will break the build unless you have Rust installed separately.
On Linux, modern distros should have Python 3.9 available already. If
you're on an older distro, you'll need to build Python from source first.
'FlagManager' allows cached access to the flag objects, takes care of
renaming flags and notifies GUI components with the hook
'flag_label_did_change'.
