Hi all:
Is the pepper-flash package safe to install? The package state’s it may be dangerous and is not maintained? Is there a better way to get flash in Chromium? Thanks for your help.
Flash in general is unmaintained and potentially dangerous 
So installing pepper-flash should be no problem.
What the chromium-pepper-flash PKGBUILD does is downloads the RPM of google-chrome from google, installs it in a fake root, then extracts pepper-flash from it, creates a install-able package from those files and installs that to your system. the warning you see is just informing you that Arch themselves do not maintain the packages or source code that the AUR uses, that’s all, that package is maintained by google for rpm based distro’s.
AJSlye:
Thanks very much for the answer.