There is a “Go to Declaration” in context menu of Atom Editor, but it doesn’t work by default. It is because Atom doesn’t scan the project to generate symbols, it depends on tags, tags can be generated by run command “ctags -R in project root”.
cmd-r can lookup symbols in current buffer (file), it doesn’t requires tags pre-generated.
cmd-shift-r can search the symbol over the whole project, it requires tags.
Go to Declaration shortcut menu is same as cmd-shift-r and typing the symbol under the cursor. It is a frequent operation, thus the hot key cmd-alt-down is assigned 。
Atom doesn’t provide the function to find all the reference to a specific symbol, yet.