The category is always added if you don't have a lang
attribute, since the extension doesn't have a default language, and doesn't have any language auto-detection feature. However, having a lang
attribute doesn't guarantee that the categoy won't be added; it is also added if the value of the lang
attribute is invalid (though as I said above, there isn't any completely comprehensive list of valid values as far as I'm aware). But, one of the ways the value can be "invalid" is if it isn't the expected capitalization, even though the actual language matching doesn't seem to be case-sensitive in most cases. As long as the actual syntax highlighting works correctly, changing the lang
attribute's value to prevent the category from being added isn't terribly important. So, is your code being correctly highlighted when you use <syntaxhighlight lang="abap">
?