Note: The copy template needs even more as we have a pr by @Bakual taking off the language folder from the core templates. I.e. it also needs to look into the core language folders for the ini files there. Would be good if a patch would include both issues.

ATM, we have only

			// Copy all files from $fromName template to $newName folder
			if (!Folder::copy($fromPath, $toPath) || !$this->fixTemplateName())
			{
				return false;
			}

in the copy() method.

I guess the fixTemplateName() method would also need to be refactored.

Setting as Release blocker.

@Bakual
Please follow up on your merged PR.

@infograf768 That's not my task and I never said I'd do that.
It's exactly as @SharkyKZ wrotes, the template copy needs to take care of all assets (language files obviously included), not just simply copy the folder. If it properly reads and copies the assets, then the language file issue is solved as well.

Duplicate #28796?

#28796 is mainly aimed at copying site template but we started there to discuss solutions.

We do not get anymore the issue with Service as stated by @SharkyKZ as it has been added to the xml.

But we still get the issue with the specific js files in media/templates/atum/js/

Cassiopea has no js files but one can imagine 3rd party templates may have some also in media.

and evidently the language files for which we get
JInstaller: :Install: File does not exist /Applications/MAMP/htdocs/testinstall/joomla40/tmp/template_copy_5ea51c4e22eff/en-GB/en-GB.tpl_atum2.ini

Let me add this comment to #28796 and see what @Bakual says about keeping one or the other.

Please test #28813