Because QtWebEngineProcess is a separate application, and does not use PySide's internal qtconf registration mechanism, ICU data fails to be found, because QLibraryInfo::location(QLibraryInfo::DataPath) returns the path to the Qt install dir, and not PySide's Qt dir.
The application would crash with output similar to:
Qt WebEngine ICU data not found at /home/qt/work/install/resources. Trying parent directory...
Qt WebEngine ICU data not found at /home/qt/work/install. Trying application directory...
Qt WebEngine ICU data not found at /usr/lib64/python2.7/site-packages/PySide2/Qt/libexec. Trying fallback directory... The application MAY NOT work.
Installed Qt WebEngine locales directory not found at location /home/qt/work/install/translations/qtwebengine_locales. Trying application directory...
Qt WebEngine locales directory not found at location /usr/lib64/python2.7/site-packages/PySide2/Qt/libexec/qtwebengine_locales. Trying fallback directory... Translations MAY NOT not be correct.
[0318/144156.653641:ERROR:icu_util.cc(178)] Invalid file descriptor to ICU data received.
[0318/144156.653736:FATAL:content_main_runner.cc(691)] Check failed: base::i18n::InitializeICU().
#0 0x7f9a8439af3e <unknown>
#1 0x7f9a843acc4e <unknown>
#2 0x7f9a84379482 <unknown>
#3 0x7f9a8437299d <unknown>
#4 0x7f9a83a97999 QtWebEngine::processMain()
#5 0x0000004009f3 <unknown>
#6 0x7f9a7ff94c05 __libc_start_main
#7 0x000000400a2f <unknown>
[19347:19347:0318/144156.841951:ERROR:child_process_launcher.cc(522)] Failed to launch child process
We need to ship a qt.conf file with
inside the libexec folder where QtWebEngineProcess is located.