sgbrowse.vim is a plugin that adds a SGBrowse command that opens your current file or current line selection in Sourcegraph. If you're familiar with the GBrowse command from vim-fugitive, it works the exact same way. In fact, sgbrowse just hooks into the GBrowse code.
It depends on many functions in vim-fugitive, and will not work if you do not have it installed.
call plug#begin('~/.cache/nvim/plugged')
Plug 'camdencheek/sgbrowse'
call plug#end()