I see no evidence of the book becoming free on its homepage: http://man7.org/tlpi/ http://man7.org/tlpi/ https://doc.lagout.org/ https://doc.lagout.org/ looks

I see no evidence of the book becoming free on its homepage: http://man7.org/tlpi/ http://man7.org/tlpi/ https://doc.lagout.org/ https://doc.lagout.org/ looks quite shady, so I guess someone uploaded their copy without copyright holder's permission.