The meteorite is part of the SuperCam Calibration Target (SCCT) on Perseverance.
From the paper "SuperCam Calibration Targets: Design and Development":
As a nod to the notion of return samples that this mission prefigures,
and for outreach purposes, we have installed a ∼11×9×1.25 mm slab from
a Martian meteorite (ref. North West Africa, NWA 10170) in the
mounting bracket of the RMI geometric target (Fig. 3m detail A). This
Martian meteorite is mounted in a no-laser region of the holder (per
SuperCam flight rules) and is not intended for LIBS or Raman analyses,
but could be interrogated by the IR spectrometer.
This meteorite was found near the Moroccan-Algerian border and was
purchased by L. Labenne at the Tucson salon from an anonymous dealer
(Fig. 4) for the Toulouse Science Museum. The meteorite was then
carried by the French astronaut T. Pesquet to the International Space
Station, during his stay from November 2016 to June 2017 (Fig. 4,
right). After his return, the meteorite was cut to be implemented in
the SCCT. Once it lands on Mars, the meteorite will have passed
through the Martian atmosphere twice and Earth’s four times.
Another paper also mentions its purpose as a practice target:
An additional element (MM), consists on a martian meteorite that
serves as practice target, and in fact as an “inverse sample return”.
Image from this open access paper: https://link.springer.com/article/10.1007/s11214-020-00777-5#Aff1