Translations:Manual:SessionManager and AuthManager/9/en

$1 and $2 are two authentication-related frameworks introduced in $3 that are intended to replace the "there can be only one!" nature of $4 (the previous authentication system), the inability to do federated login (e.g., "log in with your Google account") without using various hooks to hack around MediaWiki's focus on password-based authentication, and the inability to do session management with anything other than cookies without again using various hooks to hack around MediaWiki's reliance on PHP's cookie-based sessions.