Yes, the value in DNSLinks can be an arbitrary string. It is possible to have paths that start with IPFS or IPNS, although they may be ignored. The IPFS path can be any content path, typically using IPFS and CID to avoid additional lookups. However, you have the flexibility to use any content path or subpath from a tree. Additionally, you can perform AB testing by having different paths in different directories. It is worth noting that there are also solutions available at the DNS layer, allowing for different answers based on the continent or IP from which the request originates. This can be useful for leveraging regular DNS for AB testing purposes.

For more information on DNSLinks, you can visit https://dnslink.dev/. This resource provides further insights and details about DNSLinks.