HPFP = High Pressure Fuel Pump.
Generally you have LPFP (Low Pressure Fuel Pump) from the back at 5.8bar - this travels and is driven by the cam in the Direct Injection engines I have studied.
Behind the HPFP is a cam follower lobe, which takes fuel pressure up to 110bar (2.0 TFSI engine), or 100bar (or thereabouts, in 2.5 TFSI - Audi TTRS). This is what VAG have incorporated into what we know as DFI/PDK. It is old VW technology that people laughed at, but has now become 100% perfect for economy, quick gear changes etc.
I have not studied these 997.2 yet. Until somebody loans me a car I cannot see how it works inside. Have to log/monitor the engine sensors when driving, see what is really happening, and compare that to the original software from Porsche.
This is what HPFP looks like on VAG engine
https://imageshack.com/i/0twp001385j
This is what cam follower look like on Direct Injection engine
https://imageshack.com/i/n9wp001388j
The cam follower is a little 'thimble' that helps the fuel pass at 110bar, or whichever pressure the rail accepts it at.
These modern cars do not have fuel send to rail and 'return' like old engines. It is sent and that is it. Your injectors are not fitted on a rail but screwed into the head - very close to the piston. You should fine really good MPG from these cars, n/a and petrol turbo.
DFI is the future. I with I could afford this engine in a Porsche.. maybe one day (Carrera 2S or something).
Sorry for going blah blah I love engines.