docs: WiP Flatpak

.README.md

@@ -8,7 +8,7 @@ Recommended installation order:
 - [System Config](#syscfg)
 - [Qubes proxy scripts](#qubes)
 - [ASDF](#asdf) & plugins
-- [Newer Debian packages](#versions_check)
+- [Newer Debian packages](#newer_versions)
 - [Fonts](#fonts)
 - [kitty](#kitty) — `st`?
 - [lazygit](#lazygit)
@@ -182,7 +182,44 @@ asdf plugin add python
 for Plugin in $(asdf plugin list); { echo $Plugin; asdf list $Plugin }
 ```
 
-## Newer Debian packages {#versions_check}
+## Newer Debian packages {#newer_versions}
+
+### Flatpak
+
+- `com.github.tchx84.Flatseal`
+- `org.mozilla.firefox`
+
+#### Kicksecure Wiki
+
+- [Install Additional Software Safely](https://www.kicksecure.com/wiki/Install_Software)
+  - Qubes OS Specific  
+    Applications installed using Flatpak:  
+    Qube settings → applications tab → press "Refresh Applications".
+- [Bootstrapping a Trust path To Flathub Repository Signing Key](https://www.kicksecure.com/wiki/Dev/flatpak)
+  - WiP
+  - Not needed with package `anon-apt-sources-list`???
+    - <https://github.com/Kicksecure/anon-apt-sources-list>
+
+```sh
+% cd ~/Downloads
+% scurl-download https://flathub.org/repo/flathub.flatpakrepo
+% sed -ne 's/^GPGKey=//p' flathub.flatpakrepo | base64 -w0 -d | gpg --import
+
+% gpg --fingerprint 6E5C05D979C76DAF93C081354184DD4D907A7CAE
+pub   rsa4096/0x4184DD4D907A7CAE 2017-06-16 [SC] [expires: 2027-06-14]
+      Key fingerprint = 6E5C 05D9 79C7 6DAF 93C0  8135 4184 DD4D 907A 7CAE
+uid                   [ unknown] Flathub Repo Signing Key <flathub@flathub.org>
+sub   rsa4096/0x562702E9E3ED7EE8 2017-06-16 [S] [expires: 2027-06-14]
+
+% diff ~/Downloads/flathub.flatpakrepo /etc/flatpak/remotes.d/flathub.flatpakrepo
+2c2,3
+< Title=Flathub
+---
+> Title=Flathub - Verified and Floss (Freedom Software) - --subset=verified_floss
+> Subset=verified_floss
+```
+
+### Versions Checking Tool
 
 ```sh
 cd ~/bin