Pres pardons and limitations explained
https://www.findlaw.com/litigation/legal-system/presidential-pardon-power-and-its-limits.html
§ 1.11 Advisory nature of regulations.
The regulations contained in this part are advisory only and for the internal guidance of Department of Justice personnel. They create no enforceable rights in persons applying for executive clemency, nor do they restrict the authority granted to the President under Article II, section 2 of the Constitution.
https://www.ecfr.gov/current/title-28/chapter-I/part-1