With referendum 280 Composable Finance and Zeitgeist have successfully requested opening a channel between their respective parachain and AssetHub. The active runtime during opening the channels was polkadot-runtime v1.0.1. In this runtime, polkadot-runtime-parachains v2.0.0 is used. This crate contains the code to manage hrmp channels. In version v2.0.0, in any case it is required that both parachains that are involved in the channel opening process provide a deposit. Thus, to open channels between AssetHub and Composable Finance and AssetHub and Zeitgeist, it was required to provide the channel opening and acceptance deposits to the AssetHub parachain sovereign account on Polkadot. You can see that Composable Finance have transferred 20 DOT to the parachain sovereign account of AssetHub and Zeitgeist also have transferred 20 DOT to the parachain sovereign account of AssetHub as well.
Before OpenGov was activated, hrmp channel openings to system chains involved funding the system chain's sovereign account from the treasury, as can be seen in an old GoV1 referendum. Furthermore, a later version of the polkadot-runtime-parachains crate does also contain the logic to relieve the requesting entity of providing the channel deposit fees for the system chain. Consequently, right now we are in a transitory state where the general admin track can be used to request opening HMRP channels with system chains, but the cost of the channel deposits have to be provided by the requesting entity as the general admin track cannot control funds of the treasury.