EIP-155 defined a list of chain IDs, e.g. main net is 1 Ropsten is 2. I don't seem to be able to find a definition about its supposed value range and data size.
Quoting the yellow paper rule (287)
It is assumed that v is either the ‘recovery identifier’ or ‘chain identifier doubled plus 35 or 36’. The recovery identifier is a 1 byte value
The text says if it's recovery identifier, then it's encoded in one byte. It doesn't mention about the size for
chain identifier doubled plus.
It seems for the
chain identifier doubled plus case, one byte won't be sufficient: EIP-155 lists
1337 as the value for Geth private chains. So it seems safe to say this field (i.e. Tw) can be longer than one byte. If that's the case, shouldn't it be encoded with a length prefix?
Apart from the value
1337, is it possible for other networks to have even larger, longer chainId settings?