In the Fields dialog, the cross-reference type is named "Illustration" (singular). But all the other entries are written in plural form (bookmarks, headings, numbered paragraphs.) I suggest to rename it to "Illustrations" in English and in all localizations too.
ux team: thought you might be interested in this one.
I agree with Thomas. I suggest that also "Table" should be named to "Tables"
I'm not sure, that it is possible. The words "Illustration" and "Table" are the identifier of variable of type 'Number range'. This identifier is used in the text, which you get, when you insert a Caption. And there the plural would be false. The user can define his own 'Number range' e.g. "Screen". Then this word will be listed in tab Cross-references too.
"Drawing" is another affected cross-reference type, I adapt the summary. Regina, is it possible to replace the identifier names with new translatable display names which could be shown in the "Type" list on the left of the Cross-reference tab?
With this recent patch https://gerrit.libreoffice.org/#/c/54372/ for bug 117013 we have "Table of Figures" under Type (using Figures for image captions). And you can change that at Category to Figure, Illustration, Drawing... Works for me.