When I run the Language Editor plugin on my Elgg-supported site and examine the English language of your event_manager plugin for Elgg, I saw that some lines (if I'm not mistaken, 15 lines) had empty (' ') expressions. When I downloaded the language file to my computer and examined it using Notepad++, I saw that it contained empty values ​​from line 83 (defined as 'Short description') to line 99 (defined as 'Editor') according to the order there. And for this reason, I cannot translate it to my language in the language editor plugin. What is the reason for this? Do these empty lines have an equivalent in the Elgg site structure? Is it possible for me to delete these lines which have empty values?

These blank translations are used for conditionally adding help texts to certain forms. You should be able to translate them (or fill them in if needed).

They cause no problem for your site, so you can just ignore them if you do not need the additional help texts.