The short answer is: Ppf.esm is not part of the vanilla Fallout 4 installation. It is not a DLC file like Fallout4.esm or NukaWorld.esm . Instead, it is a ghost from a very specific and popular modding tool.
When these break, the community tool or the repair feature within Place Everywhere can generate a Ppf.esm . This file stores repaired Previs and precombined data for your specific load order. Fallout 4 Ppf.esm
Now, armed with this knowledge, you can return to the Commonwealth. Whether you are rebuilding Sanctuary, exploring the Glowing Sea, or troubleshooting your 300-plus mod load order, you will never be confused by again. The short answer is: Ppf
If you have spent any time diving into the sprawling world of Fallout 4 modding, you have likely encountered the dreaded "missing master" error. Among the most confusing and frequently searched error messages in the community revolves around a cryptic file: Ppf.esm . When these break, the community tool or the