maint: update top-level README.markdown

Write index of projects found in this repository. Since "tildegit.org" renders
README.markdown, it will provide some introduction. Also it provides me with
soothing feeling that I have understanding of what I have.

README.markdown

@@ -6,5 +6,50 @@ approach in my blog [post](./text/gemini/src/2023-07-22.1.gmi)
 
 Here is the index of things you can find in this repository:
 
-* [source of the gemlog](./text/gemini) that is currently hosted at [gemini://tilde.pink/~kaction](gemini://tilde.pink/~kaction)
+* [Source of the gemlog](./text/gemini) that is currently hosted at [gemini://tilde.pink/~kaction](gemini://tilde.pink/~kaction)
   (also available via [http proxy](https://portal.mozz.us/gemini/tilde.pink/~kaction))
+
+* [Collection of dot files](./config) together with declarative Nix profile
+  containing programs that use these dotfiles. Also some useful scripts can be
+  found in [./config/bin](./config/bin), although documentation is scarce.
+
+* Patched versions of someone's else projects:
+
+    - [Runit supervision set](./prog/lang-c/runit) ([upstream](https://github.com/vulk-archive/runit))
+    - [Meillo's mail handler](./prog/lang-c/mmh) ([upstream](http://git.marmaro.de/?p=mmh))
+    - [Nixpkgs](./nixpkgs) ([upstream](https://github.com/nixos/nixpkgs))
+
+* Several of my own projects:
+
+    - [Haskell bindings to GNU dbm](./prog/lang-haskell/gdbm)
+    - [Haskell interface to linux capabilities](./prog/lang-haskell/linux-capabilities)
+    - [commune](./prog/lang-haskell/commune) -- offline-first interface to github and gitea issues.
+    - [run-many](./prog/lang-zig/run-many) -- command line tool to run multiple commands with interleaved output.
+    - [a5](./prog/lang-tex/a5) -- collection of well-typeprinted solutions to high-school math tasks.
+    - [capwrap](./prog/lang-fasm/capwrap.fasm) -- wrapper that executes command with linux capabilities.
+
+* Collection of [scripts](./maint) and [git hooks](./git-hooks) used to maintain this
+  repository. Documentation is in script header.
+
+* Many abandoned and bit-rotten projects:
+
+   - [Experiments](./prog/lang-c/lodestar) to save couple kilobytes from binaries created by gcc.
+   - Some allocation-free [C code](./prog/lang-c/libhpl).
+   - Several projects to write [schema for real-world configurations](./prog/lang-dhall) in [Dhall](https://dhall-lang.org).
+   - [Emacs plugin](./prog/lang-elisp/nix-environment) to update buffer environment with correct `shell.nix`.
+   - [Command line interface](./prog/lang-execline/srht-ui) for the [sourcehut](https://sr.ht) forge. Superseded by
+     [tool](https://sr.ht/~emersion/hut) maintained by sourcehut's developers.
+   - GNU Bash [plugin to write .bashrc with lisp](./prog/lang-guile/guile-bash)
+   - [Nix function](./prog/lang-nix/nix-freeze-derivation) to import every file in the path into Nix store individually
+     to maximize path sharing.
+
+* Multitude of experiments in different languages that never reached even 0.0.1 version.
+
+## Communication.
+
+If you want to talk or send me a patch, you can use following email addresses:
+
+```
+$ echo fmthY3Rpb24vcHVibGljLWluYm94QGxpc3RzLnNyLmh0Cg== | base64 -d  # this is public list address (preferred)
+$ echo a2FjdGlvbkBkaXNyb290Lm9yZwo= | base64 -d                      # this is personal email address
+```