move special READMEs into doc/ and format as md

The formatting is very basic and more should probably be done, but we at
least get the files out of the root directory which in case of the
various READMEs was confusing salsa which one display as (central) README.

1 files changed, 14 insertions, 0 deletions

diff --git a/README.md b/README.md
index fb1c620f8..e17f1f441 100644
--- a/README.md
+++ b/README.md
@@ -198,3 +198,17 @@ block the correct installation of very important packages. Which option to use d
 if you are interested in the topology sorting (`Debug::pkgOrderList`), the dependency-aware
 cycle and unconfigured prevention (`Debug::pkgPackageManager`) or the actual calls
 to dpkg (`Debug::pkgDpkgPm`).
+
+
+Additional documentation
+------------------------
+
+Many more things could and should be said about APT and its usage but are more
+targeted at developers of related programs or only of special interest.
+
+* [Protocol specification of APTs communication with external dependency solvers (EDSP)](./doc/external-dependency-solver-protocol.md)
+* [Protocol specification of APTs communication with external installation planners (EIPP)](./doc/external-installation-planner-protocol.md)
+* [Howto use and configure APT to acquire additional files in 'update' operations](./doc/acquire-additional-files.md)
+* [Download and package installation progress reporting details](./doc/progress-reporting.md)
+* [Remarks on DNS SRV record support in APT](./doc/srv-records-support.md)
+* [Protocol specification of APT interfacing with external hooks via JSON](./doc/json-hooks-protocol.md)