On the Volvo XC60 2012 an optional extra is the power tailgate which you can operate by remote or a button which lifts or lowers the boot.
On mine it droops after reaching the top spot, exactly like on a regular gas strut where the gas strut has worn over time and doesn't hold the boot open.
In this video I show you my replacement of one of them, showing how to remove the boot liner and where the boot electrical harness connects to.
It doesn't fully solve the problem so make sure you watch to the end for the verdict!
(I'm not going to link to the part since I'm not 100% this part works correctly or is a suitable aftermarket part)