XF 2.0 Help me understand Xenforos IP format


I'm trying to integrate Laravel with Xenforo. The easiest and most non-intrusive way I figure is keeping each application fairly unchanged and sync its user registration, login and logout (and its databases tables).

Each time the user login in Laravel, it will trigger an event that inserts data in Xenforos xf_session.
The session_data field is a blob, which represents the following serialized array:

=> [
     "_ip" => "\x7F\0\0\x01",
     "userId" => 31,
     "passwordDate" => 0,
     "fromSearch" => false,
     "dismissedNotices" => [],
     "lastNoticeUpdate" => 1518140290,
     "promotionChecked" => true,
     "trophyChecked" => true,
     "previousActivity" => 1518140031,
I dont understand which means the IP field. Is it in octal? What are those slashes?

Thanks in advance.