If you don't have any connectors, removing the app is harmless; if you do, they'll break and need to be re-created unless Bruce is able to personally assist in that manner again.
If you know what caused the app to end up in this state, that might also be helpful for them to see if there is a way to prevent it in the future.
They are devices "tied" to the variable that you would have created on the Hub Variables page on the first place. They are sort of a legacy feature that can be used by apps that don't directly support hub variables. If you don't think you do, you probably don't, but checking your Devices page for connectors would tell you for sure (actually so should going to the App Status page mentioned in that other post, even if you don't use it to delete the app--it will list child devices).
I'd say: follow the instructions in the post I linked to above to get to the App Status page for your Hub Variables app/page. Then see if you have a "Child Devices" section at the bottom of that page, in which case you'll have your connector devices listed there. Otherwise, you'll see "App has no child devices," in which case you're good to go with the above instructions.
Remember that you can make a backup of your hub at any time, which you may want to do before performing the above in case you decide you want to revert.