Perseverance rover places its abrasion tool on 'Mount Meeker'. HazCam image from Sol 858

We don't have a mission update so we can only speculate. One plausible scenario could be to test the stability of that section of this gnarly boulder. They can test stability by using the robotic arm to place a high load on the surface, to ensure a section of the rock would not break off during abrasion or subsequent coring the rock. If it is stable they may choose to abrade (grind circular patches into rocks so its science instruments can analyze the rocks' composition) and if the results are interesting, they may then choose to obtain a rock core.

We can review the new images frequently to see what is happening (An update from the team would be awesome, but are rare on this mission).

Watch this space :)