sources.list and indextargets option for pdiffs

Disabling pdiffs can be useful occasionally, like if you have a fast
local mirror where the download doesn't matter, but still want to use it
for non-local mirrors. Also, some users might prefer it to only use it
for very big indextargets like Contents.

1 files changed, 9 insertions, 1 deletions

diff --git a/doc/acquire-additional-files.txt b/doc/acquire-additional-files.txt
index 71ce7b0cb..9110bfe79 100644
--- a/doc/acquire-additional-files.txt
+++ b/doc/acquire-additional-files.txt
@@ -85,7 +85,15 @@ file if it is available and uncompress it for you, just as it will also
 use pdiff patching if provided by the repository and enabled by the
 user. You only have to ensure that the Release file contains the
 information about the compressed files/pdiffs to make this happen.
-NO properties have to be set to enable this.
+*NO* properties have to be set to enable this!
+
+
+Additional properties exist, but these should *NOT* be set by frontends
+requesting files. They exist for internal and end-user usage only:
+* PDiffs: controls if apt will try to use pdiffs for this target.
+  Defaults to the value of Acquire::PDiffs which is true by default.
+  Can be overridden per-source by the sources.list option of the same
+  name. See the documentation for both of these for details.
 
 # More examples