The matcap files themselves (.exr files) are stored in the Blender folder at .../2.93/datafiles/studiolights/matcap
. However, you can see that even if I apply it as an Environment Texture in the World Shader, the results are still slightly different to the MatCap look - probably meaning you will need some of your own lights as well:
Matcap in Solid Preview:
![Mat1](https://i.sstatic.net/NzjCD.png)
MatCap as an Environment Texture
![Mat2](https://i.sstatic.net/4kg8W.png)
Here it is with the environment "corrected" to show only the lighting and reflections from the "matcap" texture (more similar to the preview.) You can see that although close, it is still not the same. Changing the View Transform from filmic to standard helps, but it's not perfect.
![Mat3](https://i.sstatic.net/aj6pC.png)