Comment 3 for bug 1862395

At least in the poeditor UI, there is an "overwrite old translations" checkbox to be careful of. I would assume that we wouldn't lose any work with that unchecked: https://poeditor.com/kb/importing-and-exporting-strings (famous last words).

Feel free to use the Spanish translation as a sandbox. It has exactly one translation (mine, which I could easily re-do).