How to download modified original language strings?

Hi there, I cannot find one thing to do:
We have source file, which contain keys and EN strings.
We are translating our project to CZ, this works perfecto!
When fine tuning our project, I also sometimes edit EN strings while keeping the keys, of course.
How can I download EN file with modified EN strings? Cannot find how to do it…
One workaround, on my mind, is to create EN translation, download file and upload it back as the source… but this will displey the project as 50% untranslated…

Hi Maxim, source files (updated ones too) can be downloaded in the Sources tab > Files: