The patch for issue 69264 and the corresponding commit 
24eabd1eff34673d4a93edf16f92c444cdc1ac3f seem to break the build of 
plasma-desktop since it fails with:


********* Start testing of PositionerTest *********
Config: Using QtTest library 5.15.10, Qt 5.15.10 
(x86_64-little_endian-lp64 shared (dynamic) release build; by GCC 
11.3.0), unknown unknown
PASS   : PositionerTest::initTestCase()
QWARN  : PositionerTest::tst_positions(3 per column) kf.kio.core: 
couldn't create worker: "Unknown protocol 'file'."
QWARN  : PositionerTest::tst_positions(3 per column) kf.kio.core: 
"Unable to create KIO worker. Unknown protocol 'file'."
QFATAL : PositionerTest::tst_positions(3 per column) ASSERT failure in 
QList<T>::operator[]: "index out of range", file 
/gnu/store/h3w0axvfps5j2g2wcl1hf349x0psy95s-qtbase-5.15.10/include/qt5/QtCore/qlist.h,
line 575
FAIL!  : PositionerTest::tst_positions(3 per column) Received a fatal 
error.
   Loc: [Unknown file(0)]


Reverting the offending commit seems to fix the issue. I don't know why 
this fixes it and it feels kind of hackish but it prevents me from 
updating my system otherwise.