These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 0.84 s (backtrack: 0/20).


!!! All ebuilds that could satisfy "=dev-python/pyside-6.12.0" have been masked.
!!! One of the following masked packages is required to complete your request:
- dev-python/pyside-6.12.0::gentoo (masked by: package.mask)
/Volumes/Disk 1/Repository/portage-git/profiles/package.mask:
# Ionen Wolkens <ionen@gentoo.org> (2026-10-01)
# Masked for testing the new .0 version and leave time for packages
# to catch up on support. Will likely be kept masked until 6.12.1
# is released unless there is a notable reason to need this earlier.
#
# If wanted, feel welcome to add `dev-qt/*:6/6.12.0` to package.unmask
# and report issues.
#
# Note: qtwebengine was "split" from Qt's main packaging and is now
# versioned as 6.<chromium-major>.<patch> (6.140.0 here), for now it is
# included in this mask (unmask with dev-qt/qtwebengine:6/6.140.0), but
# in the future it will be treated separately given it is not pinned and
# e.g. 6.140.0 can be used with Qt 6.11.x (aka not just 6.12.x).
#
# !!! ... however, 6.140.0 was not released yet, if you need qtwebengine
#     either do not unmask this or use qtwebengine-6.140.9999 for now.


For more information, see the MASKED PACKAGES section in the emerge
man page or refer to the Gentoo Handbook.