The’re are a lot of these on the market made by most of the big tent manufacturers , ours happens to be made by Eurohike as it was blue and was purchased in a sale at Millets.
The Eurohike adventure tarp is designed to provide some additional covered space outside of your tent, contained within the handy carry bag is a single collapsible pole, the tarp itself and some guy lines and pegs. Designed to to be draped and pegged over the top of the entrance of your tent and poled and pegged at the other end, it provides a area outside of the main tent suitable for sheltering from the rain or sun to cook or simply gaze upon the world.
At providing shelter from the sun this does an excellent job though putting it up is a little fiddly, found the best way is to do this is to peg it with a clothes peg to the tent, then peg out the rear guy lines, before moving on to the front pole and guys. I can’t comment on it’s use in the rain as “touch wood” we’ve not experienced that yet.