[Bug] FontFace API loads codicon font from hardcoded ESM source path at runtime, bypassing bundler asset processing

Reproducible in vscode.dev or in VS Code Desktop?

• Not reproducible in vscode.dev or VS Code Desktop

Reproducible in the monaco editor playground?

• Not reproducible in the monaco editor playground

Monaco Editor Playground Link

No response

Monaco Editor Playground Code

Reproduction Steps

No response

Actual (Problematic) Behavior

When bundling Monaco Editor with esbuild (or similar bundlers), the codicon font is correctly handled via CSS @font-face when using a file loader. However, Monaco also loads the font programmatically at runtime via the FontFace API using a hardcoded path that reflects the original ESM module structure:

/base/browser/ui/codicons/codicon/codicon.ttf

This path is a string literal inside JS, so bundlers cannot rewrite it during the build — only url() references in CSS and static import/require calls are processed. The result is a 404 request at runtime, visible in DevTools with initiator other (indicating a CSS-via-JS FontFace call).
Steps to reproduce

Bundle Monaco Editor ESM with esbuild using loader: { ".ttf": "file" }
Set publicPath or rely on relative paths for font resolution
Open the app in a browser and inspect the Network tab

Expected Behavior

The font URL used in the FontFace API call should either:

Use a path resolvable at runtime (e.g. relative to the script), or
Be configurable via MonacoEnvironment, similar to worker URLs

Additional Context

A request is made to /base/browser/ui/codicons/codicon/codicon.ttf (the raw ESM source path), resulting in a 404. The font still renders correctly if already loaded via CSS, but the spurious request and console error are confusing.

Start by reproducing the esbuild ESM bundle with the .ttf file loader and inspect the FontFace API request for the codicon font. Trace the runtime URL that produces /base/browser/ui/codicons/codicon/codicon.ttf, then verify the bundled app resolves the font without a 404 and preserves the expected CSS font loading behavior.