Deletion of translations identical to English source

You don't need to be concerned that people will see that the translation of these messages is missing and make a faulty translation. By default, people will not see these messages as missing, because they are defined as optional. Messages are defined as optional when their translations are expected to be identical to the original English string in most languages. They may still be translated if they must be different from English, but if they are identical, then keeping an identical string is useless.

The messages I deleted recently are defined as optional because these are labels of keyboard keys, which are the same in almost all countries. I know that they may be different in France, Spain, and a few other countries. I don't know about Denmark; if "Backspace", "Shift", or some other key have a different label on keyboards sold in Denmark, then they should be translated with these names. Otherwise, they should be taken directly from English and not translated.

If a message is not defined as optional, but its translation happens to be identical to English, then it indeed shouldn't be deleted.

Optional messages can be shown in the translation interface by clicking the "..." button at the top of the translation interface and checking "Optional messages" ("Valgfrie beskeder").

Hi Amir,

Thank you for a very thorough and excellent reply, addressing all my concerns and guiding me so nicely. You even stated the translation of the label "Optional messages" in Danish; that's just so excellent and wholesome.

In fact, "Shift" does have a diverging translation in Danish, namely "Skift". But that translation is still perfectly alive and well at https://translatewiki.net/wiki/MediaWiki:Visualeditor-key-shift/da, just as it should be.

Thank you again for such a perfect reply.