Where is /etc/issue?

the reason I ask is that I have lots of microSDs
with various images ( openwrt, raspbian )
for several boxes ( rpi1, rpi3, tinkerboard )

and it would be nice to have an easy way to know
whats on a microSD.

/etc/issue isnt ideal, but its usually present on a linux box.
a much better way is something like


since /boot is vfat, and filename works without opening the file

I gather I could create a custom file via some build-feature,
(not sure where I saw it, but prolly could find it again)
Is this an addition that the project would find useful ?
and if so, is the custom file the right way to do it ?

source /etc/os-release
echo "${PRETTY_NAME}"