Node-RED Installer 404

Symptom: the Node-RED install command downloads a 404 error page instead of running the installer.

Release asset filenames on the node-red/linux-installers GitHub repository have changed between versions — a URL that worked previously (or that's quoted in an older guide) can 404 later. Before running the install command, verify the URL resolves:

curl -o /dev/null -w '%{http_code}\n' <installer-url>

If it returns anything other than 200, check the node-red/linux-installers releases page for the current asset name and update the command accordingly.