But they were the last ones in buster. Since last June! I'm not going to downgrade them in the EE ISOs.
The up to date ones currently in the EE ISOs seem to work OK.The packages I added are from stretch and they at least work on SolydK 10. I haven't had the time to test them on SolydX 10 but I assume there will be no difference.
Actually, libicu57 isn't required with the current webkit set. That depends on libicu60.