Where is Arduino on Fedora?
It depends how you installed it. 

If you downloaded the tarball and extracted it then it's wherever you extracted it. 

If you used a package manager to install it then they could be anywhere - you should look at the package manager software fedora uses (yum? it's been a while) to see how to find what files a package installs.

If you are running a modern version of Arduino (I know Debian based packages are from the stone age) then the board manager installs will be in ~/.arduino15