Short description of error
Some translations in menus in Blender 2.90 are missing. I checked the code and found the missing translations may be the text argument from bpy.types.UILayout.operator(). Also, compared to 2.83, these translation msgid is missing in produced *.po file.
Here is a diff file of translation between 2.83 and 2.90.
Here is an example:
the code behind:
I try to replace the *.mo file by it in the 2.83 version, and everything goes right.
However as a newbie, I'm not able to fix it so I put an issue for someone who would like to involve in.
Exact steps for others to reproduce the error
Just start up in another language apart from English.