The modding support allows us to modify the translations of the main game by placing xml files in the "Localization" folder of our mod. There is a great guide available on how to do that (see https://docs.larian.game/Modding:_Localization, thanks Kevin!).

In order to add translations to the xml files, we need handles, strings that look like guids with the slashes stripped apart that identify the translations and connect the translated strings to the original strings entered in the editor. For the main game there is a huge Excel file containing all the strings and their corresponding handles. But how do we add those handles to our own custom strings?

As I made the big mistake and used my native language while building my mod (to everybody reading this: do not do this, write your stuff in English so it is easily shareable) and now would like to translate my work to English, I investigated a bit on that topic and didn't find a way to assign translation handles. I opened several source files (e.g. dialogs and root templates) and the strings don't have a handle, instead there is always some kind of unset value like "ls::TranslatedStringRepository::s_HandleUnknown" in dialogs.

PS: The modding tools are awesome and this is merely a detail question probably only a few people beside me are interested in.