On PC with enabled "mobile version" of site, looks good. Screenshot: F31758099.

This is issue on mobile devices, not on PC.

When administrator delete page and reason for deletion is very big, content goes out. See F31758074.

@Zoranzoki21: I don't think this has anything to do with "very big". Did you try with a long reason for deletion which includes whitespaces between words?

It isn't case with edit summary. See F31758080.

@Zoranzoki21: That screenshot shows no edit summary with many characters and no whitespaces in-between, so I don't know why you state "it isn't the case"?

I did some additional testing

• enabling AMC does not have any effect on the display of super long entries
• the text field for entering the reason for deletion (on Deletion log does not have maxlength restriction, so any amount of text can be entered there.

However, super long text if properly formatted (words separated by white spaces) will be displayed correctly:

• the issue is present for Edit summary on Special:RecentChanges if the text does not have white spaces
  
• on the other hand, Deletion log does not have the issue. RecentChanges will display the issue even with the option "Use non-JavaScript interface".

Compare:

RecentChanges	Deletion log

Thanks @Etonkovidova for testing this. You done it much better than me. I can tell you only to I agree with all above you wrote.

And I have question, should we remove AMC tag if this isn't issue with it?

@Zoranzoki21 yes, Advanced Mobile Contributions can be removed for this task - thanks!

In T250308#6072535, @Etonkovidova wrote:

@Zoranzoki21 yes, Advanced Mobile Contributions can be removed for this task - thanks!

Done.