Viewing and changing your data on the sites you visit?

Question

Google Chrome

When installing browser extensions, this thing appears: viewing and changing your data on the sites you visit - in simple human language without scientific terminology, what does this mean?

Answer 1

So you went to the page with the description of cats. And if the extension has permission to "view and change", then it can also "read" this description. And he can even change it.
Sometimes it's useful, and it's meant to be. The ad blocking extension scans the content of the page, finds ads, and cuts them out. Or an extension that automatically translates into another language, for example.
Sometimes this can be harmful. For example, on the page of your bank, look at the balance and change the account number to which you are making the transfer.