[SELF-HOSTED] How to call custom widgets hosted on Internet behind corporate proxy?

Hello. I don’t have found on code repo how to add an http_proxy var env that node-fetch, used by grist, could use to fetch the custom widgets manifest (GRIST_WIDGET_LIST_URL) or a new custom widget by url from an Internet behind a corporate proxy. Is it possible or it needs a new feature ?
On Choose Custom Widget page, I have an error: ERROR: Error: Request to https://.../o/<myorg>/api/widgets failed with status 500: Internal Server Error (FetchError: request to https://.../widget-list.json failed, reason: connect ENETUNREACH ???.???.???.???:443)
Thank you.

For anyone finding this, this issue moved to Github repo, and got fixed: Fetch Url Widget Repository behind corporate proxy · Issue #1238 · gristlabs/grist-core · GitHub. Thank you @Tristan_Robert for the fix!

alternatively, I suppose we can put the custom widgets in our isolated server, right? So Grist doesn´t need to connect?