+ * Make things happen when buttons are pressed and forms submitted.
+                "ext-pdo_sqlsrv": "For MSSQL databases on Windows platform"
+                "ext-libsodium": "Provides a modern crypto API that can be used to generate random bytes."
+                "ext-mbstring": "For best performance"
+ * @param string $username Username, saved in lowercase.
+ * @param string $password Password, will be hashed before saving.
+ * @param string $email User's email address.
+ * @return int The new user's ID number in the database.
+ * Get where a user's account actually is.
+ * @return string "LDAP", "LOCAL", "LDAP_ONLY", or "NONE".
+ * Checks the given credentials against the database.
+ * Check if a username exists in the local database.
+ * Checks the given credentials against the LDAP server.
+ * Check if a username exists on the LDAP server.
+ * Generate a TOTP secret for the given user.
+ * Save a TOTP secret for the user.
+ * 500 most common passwords, to be used in stopping idiots from having really bad passwords.
+ * Checks a given password against the list of the 500 most common passwords.
+        "title" => "404 error"
+ * I18N string getter.  If the key doesn't exist, outputs the key itself.
+ * I18N string getter (with builder).    If the key doesn't exist, outputs the key itself.
+ * @param array $replace key-value array of replacements.
+ * result will be "hello 123".
+ * Checks if an email address is valid.
+ * @return boolean True if email passes validation, else false.
+ * Check if the previous database action had a problem.
+// Base URL for site links.
+// If you want to have additional password requirements, go edit action.php.
+// like CaPs45$% is not actually a great idea.
+// Encourage users to use 2-factor auth whenever possible.