TYPO3 Core

That is the subcategory label and IMO I won't say it's superflous. There may be sections
having multiple subcategories for a category (login) and therefore having them separated
is good. Not sure if we should hide it if it os only one subcategory for the category.

Note: Not having a `subcategory` defined in the `ext_conf_template.txt` will put them
automatically into the `Other` subcategory.

So I won't say that this is a bug/superflous but a feature which make sense.

If there are no other sub-categories, I think it makes no sense to display "Other". Only if there are other subcategories.

However, it is not a hill I am willing to die on. I just noticed it, because the behaviour changed between 11 and 12.

I guess, if you are bothered by it, you could add a subcategory always in your extensions and name it appropriately. https://docs.typo3.org/m/typo3/reference-typoscript/main/en-us/UsingSetting/TheConstantEditor.html#typoscript-syntax-constant-editor-keys-cat-custom-subcategories