Two different schemes. uBlock loads privately-constructed filtersets which are used to decide what net contents to block. (That blockage can be customized per-

Two different schemes. uBlock loads privately-constructed filtersets which are used to decide what net contents to block. (That blockage can be customized per-site in advanced mode.) Each FF container keeps content associated with one or multiple sites 'isolated' (in theory) so they can't be 'seen' by sites in other containers ... all in the browser.