I made my question a bit vague, so let me indeed elaborate. The source code is indeed protected under copyright laws and such situation is non-negotiable.

What I exactly asked for, is about modifications to the resulting web page that only I can see.

And my question is about the copyright laws’ protections on the latter. Precisely, if these are applied also there.

To recap on, if I go into developer tools in my browser, and let’s say, cut out some content I do not want to look at (in a similar manner as something content blocker extensions would do on a regular basis for me), then am I breaching these protections?

Or in even simpler words, am I breaching these protections when I simply want to save on my bandwidth?