I agree that PDFsam Basic does provide SOME of the functionality of PDFmod, and one feature PDF Mod lacks: batch reshuffling odd+even pages. But it lacks one particular feature I consider important for ordinary users: (graphical) shuffling. Apart from that, the simplicity of PDF Mod is what appeals to me. I'd even consinder to install it by default for every user. That is why I urge to reconsider your decision to either include PDF Mod (Gnome) or PDF shuffler (https://sourceforge.net/projects/pdfshuffler/). Both provide an intuitive way to add, remove, and REARRANGE pages, a common task when handling PDFs. Apart from that, I was irritated by PDFsam advertising its premium features. One can disable the notifications but they stay visible. Promoting ONE vendor irritates me, e.g. Master PDF Editor is an excellent choice, too, if one wants to buy a licensed PDF tool.

Well, yes, upstream issues. But Solus switched to TB60 and since then, the previously correct localization is broken again.
The workaround to uninstall and reinstall the Lightning XPI to correct the announg mixture of language (TB is german, L is english) doesn't work since there's no XPI 6.2 for TB60 to download.
Please investigate the cause of this glitch, this should affect ALL non-english users!