I was originally going to post this as a reply to this topic:
But, as that’s been locked, I’ll leave it here as a possible solution if anyone else has the problem:
As per the topic linked above, none of the Chromium-based browsers I installed on Manjaro would launch. Spinning cursor for a few seconds and then nothing. I had this happen with Brave, Ungoogled-Chromium, Yandex and Vivaldi.
I tried re-installing and updating via Pacman but no change. So I tried launching Chromium via the command line and got the following error:
[87047:87047:0925/150214.420071:ERROR:platform_shared_memory_region_posix.cc(217)] Creating shared memory in /dev/shm/.org.chromium.Chromium.eheJ9L failed: Permission denied (13)2 [87047:87047:0925/150214.420231:ERROR:platform_shared_memory_region_posix.cc(220)] Unable to access(W_OK|X_OK) /dev/shm: Permission denied (13)3 [87047:87047:0925/150214.420249:FATAL:platform_shared_memory_region_posix.cc(222)] This is frequently caused by incorrect permissions on /dev/shm. Try 'sudo chmod 1777 /dev/shm' to fix. 4 [0925/150214.440335:ERROR:elf_dynamic_array_reader.h(64)] tag not found 5 zsh: trace trap (core dumped) chromium
Per the suggestion in the error message
sudo chmod 1777 /dev/shm fixed the problem and all Chromium based browsers are now working fine.