Extension does not detect additional category, how to change its code?

[dapinna]

Hello,
I read the previous messages and I see that not only the only one to have problems with extensions that do not allow filtering of queries like k2.

In addition to asking the developer of the extension to add the functionality (which is quite difficult) to make manual modifications, they also require repeating the change in the event of an update.

For me this second solution is not a problem ... but I don't know what kind of code I have to look for and what to replace it with.

Could you give some more information?

Thank you :-)

Edit:
the modules I am using / testing are the following:

• BM Slider For K2
• SP Featured Slider for K2
• Article Scroller (SP Page Builder)