video: usage of `StdVideoEncodeH265ReferenceListsInfo->RefPicList0`

Hi, I'm back with another question about video encode.

The spec says that RefPicList0 are defined in terms of the H.265 spec:

> RefPicList0 and RefPicList1 as defined in section 8.3.4 of the [ITU-T H.265 Specification](https://registry.khronos.org/vulkan/specs/1.3-extensions/html/vkspec.html#itu-t-h265) where each element of these arrays either identifies an [active reference picture](https://registry.khronos.org/vulkan/specs/1.3-extensions/html/vkspec.html#encode-active-reference-picture-info) using its [DPB slot](https://registry.khronos.org/vulkan/specs/1.3-extensions/html/vkspec.html#dpb-slot) index or contains the value STD_VIDEO_H265_NO_REFERENCE_PICTURE to indicate “no reference picture”;

However, section 8.3.4 of the H.265 spec refers to the decoding process, which is a bit confusing.

1. What exactly is this field used for? It's not included in the headers, so it must inform the implementation-side encoder state, right?
2. Should it contain all active references, or just those active references used by the current picture?

The same goes for the H.264 equivalent, obviously.

Thanks in advance!