No la instalo. Me dice que archivo dañado.

good

La utilizo en google chrome pero cuando la voy a instalar en firefox me dice que Se abortó la instalación porque parece que el complemento está dañado.

tl;dr: If you see "appears to be corrupt", search and install ZeroOmega, a fork of this extension. Be careful not to install some other malicious ones!!!

Some of you may see that "the add-on appears to be corrupt". It is because google has upgrade extension manifest v2 to v3 and this plugin is no longer maintained. There is a community fork of this plugin called ZeroOmega available on github: zero-peak/ZeroOmega. Someone upgraded it to v3 manifest so is able to be installed. Also, be aware that some SwitchyOmega copies contain malicious code and will inject unsafe code. Be careful with that!