Why do some pages in a shop has NOINDEX, FOLLOW?

Some articles has noindex on its page but I can’t figure out why.
What it depends on? How to get rid of noindex?
It is said in one method “If product details are accessed by vendor url view must not be indexable”. How to determine that it is accessed by vendor url? And actually I don’t really understand what it means

Yeah, I saw this. And I think now I understand what it means “accessed by vendor”, thanks. Seems that it is not the case
But I still don’t know why NOINDEX appears on that pages. What can influence it? I didn’t find any info on the internet

no information about noindex on the whole internet? i can’t belive that.

Have I incorrectly formulated a question?
I know what it is. I don’t need it on my pages and I don’t know what is the reason why it appears on some articles pages. How did oxid determine that there should be this tag? Is there a specific option in a shop admin? Or what? I didn’t find any information exactly about it

Didn’t you read the soruce code? or the comments? there is no room for misunderstanding unless you have never used the shop frontend.
“when product page is accessed over vendor or manufacturer views, it should be not indexed”.
have you never heard of duplicate content?
If you get noindex tag on regular product pages accessed over categories, you need to provide some additional information about your shop and seo modules.

I figured out the reason. That pages are in manufacturer category and they are duplicates of articles in regular categories. But there is no general manufacturers page in my shop and I can’t visit any specific manufacturer page despite the fact that such subcategories exist in admin and they are active. I can access that articles pages only if I specify url directly
Just interesting why manufacturers page doesn’t exist but you can still access articles in this category?

Nevermind. The question is closed. Thanks for help

How to mark it solved?

There are several sources stating that canonical and noindex should not both be used on the same page, and that’s just what oxid does, there is also a bug entry for this: https://bugs.oxid-esales.com/view.php?id=6201, so this comment “when product page is accessed over vendor or manufacturer views, it should be not indexed” is kind of outdated.