I'm guessing your referring to this commit:
itflow-org/itflow61c9c0c
Basically when your in a ticket and you choose to invoice the Ticket using the invoice ticket button.
It now calculates the price for you based off total time you worked in a ticket rounded up to the nearest 15 minute mark in decimal format and then multiplies it by the client rate, also adds an item line called Service [Hourly]
so for example lets say you have the client rate set to 200.00 an hour, if you worked a ticket total time 5 minutes, it will round it up to 15 minutes convert it to decimal and multiply by the client rate.
As a result: Quantity would be 0.25 and price will be 50.00
These field values can be modified if you choose to do so.
It just makes invoicing a ticket a little more automatic when you go to bill your client.
Also to note if your client rate is 0 then the price will be 0 but can be modified