Looking into jspm and, like Skypack, I can‘t find anything on subresource integrity support. Unless I’m missing something, these new crop of ESM-based CDNs – while they sound great otherwise – are basically backdoors waiting to happen.
Skypack issue: https://github.com/skypackjs/skypack-cdn/issues/135
jspm issue: https://github.com/jspm/project/issues/92
At least the Deno folks seem to be discussing and working on it: https://github.com/denoland/deno/issues/200
This is my personal Mastodon.