Only Delphi 6 and 7 used DDP files (still a nice concept: diagrams to help understanding your DFM files)
A long time ago, I wrote a stackoverflow answer and later a blog post on how to find and get rid of empty DDP files as both Delphi versions had the habit of creating them:
- Delphi 7 turn off creation of DDP files – Stack Overflow [WayBack]
- Blast from the past: Deleting empty Delphi .ddp files
The blog post was when I helped moving an ancient Delphi project to a more modern Delphi version (due to some personal stuff going on I never finished it) and I never used such old Delphi stuff again.
This week that answer got quite a bunch of upvotes on the stakcoverflow answer which means people are still using Delphi 6 and 7 based code. Who’d ever thought that 15 year old versions would still be used today?
–jeroen