[Quoth]

Depends on if it's the Browser, Router, OS (windows, Mac, Linux or a 3rd party tool on one of those) or the ISP.
All exist and are different. I discovered pointless on the Kindle, because it blocked all books not bought from Amazon, and no parental per book settings.

I discovered the Huawei router settings didn't actually work. Other routers have worked.

Experiment with your computer. Create a separate user account!

Only the ISP and Router ones can't easily be bypassed and only if they block a site for EVERYONE. I know 9 yo kids that could block their parents and not vice versa.

Or make it up unless the OS and year is clearly identified.

Edit
P.S. The main issue with Huawei, and GCHQ agrees, is bugs in their software. It's ZTE that's the Chinese State Telecom outfit. Huawei usually lose out to ZTE in China, or in Chinese sponsored African projects. They are not American, that's Trump's objection.