I know these connectors. They are hinged.
The brown part needs to be lifted straight up, and it will hinge up and away from the cable.
Place a fingernail between the brown part and the cable at each end, and pull up, it needs a significant pull to unlatch. As long as you pull up on both ends, you should be safe.
But please remind, these connectors are VERY FRAGILE, and i cannot count how many times i've had to clean up the mess, left by unknowingly people who has broken these connectors. A plus is that the pull-up kind of connector on the picture is one of the most durable ones. The ones you pull on the brown part in the direction of the cable, are MUCH more fragile, and I even manage to break the sometimes when i fuck up.
// Per.