Espruino command-line app error: No Ports Found

Am I right in thinking you couldn't use Web Bluetooth from Chrome on
the desktop to connect either?

I don't want to, since I see Chrome as a security concern. I tried Opera with all the neccesary settings for Web BT enabled but the Web IDE did not list Web BT as a port. Here's the log:

No chrome.serial - Chrome Serial disabled
No chrome.sockets - Chrome Socket disabled
WebSocket relay support enabled - running in web browser
serial_frame: Not running inside an iframe
UTF8 Library loaded successfully
No chrome.storage API - disabling Offline mode
GET window.localStorage = null
Initialising SettingsConsole
Initialising Utils
Initialising Config
Initialising HTML
Initialising Notifications
Initialising Status
Initialising App
Initialising File
Initialising Code
Initialising Serial
  - Initialising Serial Web Audio
  - Initialising Serial Web Bluetooth
  - Initialising Serial Web Serial
Serial> serial.getPorts exists - grab known devices
  - Initialising Serial Websocket Relay
  - Initialising Serial Emulator
Initialising SerialWebSocketRelay
Initialising Terminal
Initialising CodeWriter
Initialising Modules
Initialising Env
Initialising Flasher
Initialising FlasherESP8266
Initialising EditorBlockly
Initialising EditorJavaScript
Initialising Send
Initialising MenuPortSelector
Initialising MenuSettings
Initialising MenuFlasher
Initialising SettingsAbout
Initialising SettingsFlasher
Initialising BoardJSON
Initialising VersionChecker
Initialising Compiler
Initialising Assembler
Initialising GetGitHub
Initialising Unicode
Initialising Minify
Initialising Tutorial
Initialising Webcam
Initialising FontSize
Initialising UiMode
Initialising URLHandler
Initialising CodeLink
Initialising Project
Initialising Testing
Initialising Notification_Sound
Initialising Tern
Initialising Debugger
Initialising Tour
Initialising SettingsProfile
Initialising HelpLinks
Initialising Arrows
Initialising Storage
Initialising KeyShortcuts
Initialising TerminalLogger
Initialising CoreModules
Initialising Pretokenise
Initialising SaveOnSend
Initialising SetTime
Loaded code from local storage.
serviceworker> active
Handling URL \"https://www.espruino.com/ide/#\"
ERROR: getURL(\"/serial/ports\") error : HTTP 404
/serial/ports doesn't exist - disabling WebSocket support

Is Bluetooth enabled in the Bluetooth Manager on the desktop?

Yes, "standard" BT scanning works.

And do you have the device firmware packages installed on your OS? Sometimes folks don't install them because they're non-free but then it breaks a bunch of stuff

The BT firmware is not listed by fwupdmgr get-devices

I'm not really sure what to suggest - you may have some luck adding a $5 bluetooth USB adaptor and then blocklisting the driver for whatever existing bluetooth adaptor you have? That could be the easiest way in the end.

I will try that, thanks.