Document XBPS cache-bypass refresh

README.md

@@ -76,7 +76,7 @@ metadata, and install the released package:
 sudo install -d -m 0755 /etc/xbps.d
 echo 'repository=https://git.bongbetic.com/xavierk/Fenris-xbps/raw/branch/stable/x86_64' \
   | sudo tee /etc/xbps.d/fenris.conf
-sudo xbps-install -S fenris
+sudo xbps-install -M -S fenris
 ```
 
 XBPS requires remote repositories to be signed. On the first refresh it
@@ -88,9 +88,12 @@ available at
 For later updates, always refresh first so XBPS fetches the current index:
 
 ```bash
-sudo xbps-install -Syu
+sudo xbps-install -M -Syu
 ```
 
+The `-M` flag bypasses XBPS's on-disk repodata cache. It is required when
+checking for a newly published package through Gitea's cached raw-file URL.
+
 The runit service remains dormant after installation. `fenris monitor resume`
 creates `/var/service/fenris-collect`; pause removes that link and records a
 deliberate disable in the observation history.