data-link,data-ds,data What are the attributes of -list? Where is the value? js? Or css?

For example, I got a template and wanted to change it, but it seems that the data-link cannot be changed. The link after clicking always reports an error
This page was not found
Cannot be found The web page corresponding to the following URL: file:///C:/vote/undefined-undefined.html
I changed the data-link to the absolute path of the file I want to connect to. Maybe the method is wrong, please help me! ?

Reply to discussion (solution)

This is your own decision. You can use javascript to read

custom tag~~ ~

Agree with the above, the business needs to set

custom tags ~~~
Where can I find it? .css?.js?

I can’t see it anywhere. He just wrote it casually.