Looks good to me for what I know as programmer, but none-translator :)
While at it, for consistency the other tab titles could also get a "@title:tab" UI marker context?
In general I am surprised how little usage of the UI markers are made in general. At the time when I wrote the main code of Okteta, it seemed good practice to add them everywhere, and so I did. Working on other KDE projects since I am confused why no-one else seems to use it... so a bit unsure when to use and when not.