Error: Please use $(ref:runtime.getURL) in Firefox nightly 90.0a1

[koobs]

Summary

Newly observed error reproducible in Firefox nightly. I am not sure what the first reproducible build was, but I update almost every day. Conex features (at least search, switching groups, toolbar menu) do not seem to be impacted.

Environment

OS: Windows 10 Pro 20H2 19042.964 Firefox: 90.0a1 (2021-05-06) (64-bit) Conex: 0.9.7

 Error: Please use $(ref:runtime.getURL). conex-background.js:387
    fillContainerSelector moz-extension://97df41d0-c85e-4265-96b3-814ca58fa46d/conex-background.js:387

Also seeing an additional instance of this at a different code line:

 Error: Please use $(ref:runtime.getURL). 2 conex-background.js:251
    storeScreenshot moz-extension://97df41d0-c85e-4265-96b3-814ca58fa46d/conex-background.js:251

Additional Notes

I recently added the Containerise extension, which may be contributing (thought functionality of both extensions doesn't appear impacted). However, disabling the Containerise extensions, the above two Error: Please use $(ref:runtime.getURL). conex-background.js are still observed.

• It's interesting to see storeScreenshot methods mentioned, given I have the Save screenshots option disabled

• Enabling create tab thumbnails (careful: this can cause performance issues) (I disable this normally), adds an additional error to console:

[Exception... "Data conversion failed because significant data would be lost"  nsresult: "0x80460003 (NS_ERROR_LOSS_OF_SIGNIFICANT_DATA)"  location: "<unknown>"  data: no]
    normalizeError resource://gre/modules/ExtensionCommon.jsm:752
    recvAPICall resource://gre/modules/ExtensionParent.jsm:950

At present there are two reproducing cases

1. Opening a url that results in a '' has experienced a network protocol violation that cannot be repaired.' error page (only a single Error: Please use $(ref:runtime.getURL). is observed (gandi.net at present)

2. Opening a page that loads correctly, which results in multiple errors in console. See screenshot below:

Screenshot