"Electrum" is a "Bitcoin ONLY" Wallet. However, there are many many "clones" (aka "forks") based on the original Electrum code that have been created for use with various altcoins. Unfortunately, a lot of the developers of these clones have chosen to call their modified program "Electrum-XYZ" where XYZ is the short code for the coin... This often leads to confusion with the original Electrum and people end up downloading the wrong thing and wondering why it isn't working and their coins/history don't show up.
For instance:
- Electrum-LTC is for Litecoin
- ElectronCash is for Bitcoin Cash
- Electrum-VTC is for VertCoin
and... Electrum-XVG is for Verge.