Spec unclear about what 'level' should be filled with in streams that don't conform to a level

[aconverse]

The spec is unclear about what 'level' should be filled with in streams that don't conform to a level.

From the spec:

Codecs Parameter String
DASH and other applications require defined values for the 'Codecs' parameter specified in RFC-6381 for ISO Media tracks. The codecs parameter string for the VP codec family is as follows:

<sample entry 4CC>.....
...

All parameter values are expressed as double-digit decimals. Their semantics are explained in the VPCodecConfigurationBox Semantics section above.

For example, codecs="vp09.02.10.10.01.09.16.09.01" represents VP9 profile 2, level 1, 10-bit YUV content, with 4:2:0 chroma subsampling, ITU-R BT.2020 primaries, ST 2084 EOTF, ITU-R BT.2020 non-constant luminance color matrix, and full-range chroma/luma encoding.

Mandatory Fields
sample entry 4CC, profile, level, and bitDepth are all mandatory fields. If any of these fields are empty, or not within their allowed range, the processing device SHALL treat it as an error.

So what should 'level' be filled with for streams that don't meet any level?
Same for vpcC?