docs: update pot/cookie info

README.md

@@ -78,7 +78,8 @@ E.g. https://github.com/jeb5/YouTube-Subscriptions-RSS
 ## cookies
 
 > [!WARNING]
-> Your account **MAY** be banned when using cookies !
+> Your account **MAY** be banned when using cookies ! Consider using a
+> throw-away account.
 
 E.g. from Chromium:
 
@@ -86,10 +87,51 @@ E.g. from Chromium:
 yt-dlp --cookies-from-browser chromium --cookies cookies.txt
 ```
 
+Or using an add-on: https://addons.mozilla.org/en-US/firefox/addon/cookies-txt/
+
+## pot token
+
+Youtube has started requiring proof-of-origin tokens for some players,
+and it may help not getting hit with the "sign in to confirm you are not
+a bot" together with cookies.
+
+Either add a manually generated POT to the config: `po_token =
+"{TOKEN}"` or, set up bgutils[1] with the youtube extractor to do POT
+generation automatically.
+
+```
+pipx install yt-dlp
+pipx inject yt-dlp yt-dlp-get-pot
+pipx inject yt-dlp bgutil-ytdlp-pot-provider
+```
+
+Then change the `provider.youtube` option for `cmd` to the `yt-dlp`
+binary in the modified venv, e.g. `/home/varl/.local/bin/yt-dlp`.
+
+On the same machine, run the bgutils http server, e.g. with compose:
+
+```
+ bgutil:
+      image: brainicism/bgutil-ytdlp-pot-provider
+      container_name: bgutil
+      restart: unless-stopped
+      ports:
+        - 4416:4416
+```
+
+If using default ports and it's available on localhost, `yt-dlp` will
+pick up the plugin automatically and can be verified in the logs.
+
+[1]: https://github.com/Brainicism/bgutil-ytdlp-pot-provider
+
 ## scheduling
 
 ### systemd
 
+> [!TIP]
+> Remember to change the `ExecStart` path to the venv'ed `yt-dlp`
+> binary if using it.
+
 `~/.config/systemd/user/subsyt-archival.service`
 ```
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