what does this do??? /[\\/]electron-prebuilt[\\/]/.test()

I cloned a Electron React Boilerplate repo and in the main.js saw this in the code:

if ( process.defaultApp || /[\\/]electron-prebuilt[\\/]/.test(process.execPath)

What is this called and what does it do? /[\\/]

I have never seen this. I also do not have a keyword to search Google because I have no reference term to search.