@jrieken hi, it might be a good place to also discuss an issue I stumbled upon. In this case, the original renderCodicons functions and the whole codicons.ts file is placed in vs/base/common/ module. From there it's not possible to import $, reset, append or any other function from dom.ts as it's placed in browser directory. Here, I solved this problem by creating a new codicons.ts file inside vs/base/browser, but let me know what's your preferred solution.
However, in many other cases (eg. codelensWidget.ts, viewLineRenderer.ts#renderViewLine to name a few) which are placed outside of browser directory, but require usage of $, I can't see any general solution. Do you have any idea how to tackle that problem? Or maybe there's no one way and it's better if we discuss each of the cases in a separate issue.

Here, I solved this problem by creating a new codicons.ts file inside vs/base/browser, but let me know what's your preferred solution.

I think that's good like that. An alternative would be src/vs/base/browser/ui/codicons/ but moving things around later is not hard.

However, in many other cases (eg. codelensWidget.ts, viewLineRenderer.ts#renderViewLine to name a few) which are placed outside of browser directory, but require usage of $, I can't see any general solution

We have a "special" rule that says that everything inside "editor/contrib" is implicitly in the browser layer. It shouldn't generate a warning when importing from base/browser-layers there. Tho, I would suggest that we leave the rest of the renderCodicon-adoption to the team. It is a good and simple enough sample to get everyone involved into the trusted types effort.