こんにちは TAG-さん!

I'm requesting an early TAG design review of Expose resource dependency in Resource Timing.

We plan to expose the dependency of the resources from RUM (real user monitoring) data. For a resource that's loaded from network, the "initiator info" points out what preceding resource triggered the acquisition of such resource.

As nicjansma@ points out here, the data exposed by this proposal is a RUM version of RequestMap tool. The RequestMap tool can be a good demonstration of the data to be exposed.

• Explainer¹:https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/ResourceTimingInitiatorInfo/explainer.md

• User research: Optimizing content delivery speed greatly improves user experience by reducing delays and frustration from slow-loading websites. Websites and CDNs utilize resource dependency data to determine the sequence of resource loading, allowing them to minimize delays caused by dependencies and anticipate resource requests. This proactive approach accelerates content delivery. Additionally, resource dependency information aids in tracing rogue resources, mitigating online threats and strengthening security.

• Security and Privacy self-review²: https://github.com/MicrosoftEdge/MSEdgeExplainers/blob/main/ResourceTimingInitiatorInfo/explainer.md#securityprivacy-considerations

• GitHub repo:https://github.com/w3c/resource-timing

• Primary contacts: Guohui Deng(@guohuideng2024), Microsoft.

• Organization/project driving the design: Microsoft and Google

• This work is being funded by: Microsoft and Google

• Incubation and standards groups that have discussed the design:
  github discussion: Resource initiator information to enable creation of dependency trees w3c/resource-timing#263
  WebPerf WG minutes: https://docs.google.com/document/d/1BxWvz6ymLAjl2-Ofy7rEsz5TaYzEdVDVIcv8NKZPdQU/edit?tab=t.0#heading=h.ewupa44m8fm7

• Standards group(s) that you expect to discuss and/or adopt this work when it's
  ready: WebPerfWG

• Multi-stakeholder feedback³:

  • Chromium comments: planning to prototype this and work with the WebPerfWG.
  • Mozilla comments: TBD
  • WebKit comments: TBD

• Major unresolved issues with or opposition to this design: Only one single "initiator" is reported for a resource. When JS fetches resource, multiple JS scripts may be involved. In this case, it's very desirable that we precisely define how we select the "initiator" so the Interoperability between different web browsers can be ensured.

• [ x] I have reviewed the TAG's Web Platform Design Principles