[antsar]

Yes. This is frustrating. Notable examples:

Updating an ESPHome device config requires network to build/compile the image. [0]

Viewing your Integrations page leaks a list of integrations you are using to "brands.home-assistant.io". [1]

[0] https://community.home-assistant.io/t/esphome-completely-off...

[1] https://community.home-assistant.io/t/wth-why-are-brand-icon...

[stragies]

Is the certificate for that domain pinned? If not, just host it locally. In fact, I'm going to try doing that. Have you already checked the Docs? Somebody probably already published a gist somewhere with the needed path

[XorNot]

Locally hosting platform IO is definitely on my to-do list but it is a problem which looks vast.

I have SQUID doing TLS MITM in front of it right now, but that doesn't get me really to "offline builds".