ClaytonComing soon to #postmarketOS Duranium...
System extensions!
Joe | 🇵🇸 | 🧑💻@craftyguy Is this "extensions" like the layering method that the immutable fedora offers (Silverblue/Kinoite)?
justsoup 
@joe9nf @craftyguy No, this is systemd-sysext, which just layers files on top of /usr/ so these new files (usually binaries) can be added without actually modifying /usr/ in actuality
Dr0id@justsoup @joe9nf @craftyguy so, for example, I could install nmap and use it as a hedge without that meaning the modification of the system???
@anyDr0id @joe9nf @craftyguy Technically yes, if you made an erofs or squashfs image out of the diff from your system. Probably better to use coldbrew or a container for that.
Bruce Elrick"""
When one or more system extension images are activated, their /usr/ and /opt/ hierarchies are combined via "overlayfs" with the same hierarchies of the host OS, and the host /usr/ and /opt/ overmounted with it ("merging").
"""
https://www.freedesktop.org/software/systemd/man/latest/systemd-sysext.html