Add missing files to texmf

Hi,

Is there any way to add the missing component to a CTAN package, which is place in the sandbox ? AFAIK the ```/app``` is not writable. So there is no way to run ```mktexlsr``` with ```flatpak run command```. This also happens to the Flatpak Texstudio.

No source file or test is named. Reproduce the missing CTAN component with the flatpak run command, then inspect how texmf is populated under /app and how mktexlsr is invoked; done means the component is available in the sandbox and the Flatpak workflow can use its files.

Written by the indexing model from the issue text.