✨ [RUM-6798] Capture resource content type

[bdibon]

Motivation

Web Browsers are about to support the PerformanceResourceTiming.contentType property, this will enable the browser-sdk to add a content type to resources that have not been manually retrieved via the fetch or XMLHttpRequest APIs.

Changes

• Update typing to reflect the new contentType property on resource entries
• Add types on the RUM Event to reflect the recently added resource.response.headers (see RUM-14562 Add request and response headers to resource schema rum-events-format#351)
• Process the PerformanceResourceTiming and set resource.response.headers["content-type"] when relevant
• Add unit tests
• Add e2e tests

Test instructions

Send events to intake (from FIREFOX!), your resources (but manual fetch/XHR calls) will have the new content-type field.

Checklist

• Tested locally
• Tested on staging
• Added unit tests for this change.
• Added e2e/integration tests for this change.
• Updated documentation and/or relevant AGENTS.md file

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[datadog-official]

✅ Tests

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

🎯 Code Coverage (details)
• Patch Coverage: 60.00%
• Overall Coverage: 76.75% (-0.01%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: a958fcd | Docs | Datadog PR Page | Was this helpful? React with 👍/👎 or give us feedback!}

[cit-pr-commenter-54b7da]

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum	174.43 KiB	174.52 KiB	+94 B	+0.05%	✅
Rum Profiler	6.16 KiB	6.16 KiB	0 B	0.00%	✅
Rum Recorder	25.24 KiB	25.24 KiB	0 B	0.00%	✅
Logs	56.84 KiB	56.84 KiB	0 B	0.00%	✅
Flagging	944 B	944 B	0 B	0.00%	✅
Rum Slim	130.11 KiB	130.21 KiB	+94 B	+0.07%	✅
Worker	23.63 KiB	23.63 KiB	0 B	0.00%	✅

🚀 CPU Performance

Pending...

🧠 Memory Performance

Action Name	Base Memory Consumption	Local Memory Consumption	𝚫
RUM - add global context	26.64 KiB	26.13 KiB	-521 B
RUM - add action	51.02 KiB	51.09 KiB	+70 B
RUM - add timing	26.14 KiB	26.41 KiB	+275 B
RUM - add error	54.89 KiB	55.11 KiB	+218 B
RUM - start/stop session replay recording	25.07 KiB	25.76 KiB	+706 B
RUM - start view	449.29 KiB	448.70 KiB	-607 B
Logs - log message	44.45 KiB	44.66 KiB	+217 B

🔗 RealWorld

[bdibon]

recheck

[bdibon]

I have read the CLA Document and I hereby sign the CLA

[bcaudan]

Nice 👍

[bdibon]

/to-staging

[gh-worker-devflow-routing-ef8351]

View all feedbacks in Devflow UI.

2026-03-09 14:42:34 UTC ℹ️ Start processing command /to-staging

---

2026-03-09 14:42:41 UTC ℹ️ Branch Integration: starting soon, merge expected in approximately 0s (p90)

Commit a958fcd45d will soon be integrated into staging-11.

---

2026-03-09 15:00:05 UTC ℹ️ Branch Integration: this commit was successfully integrated

Commit a958fcd45d has been merged into staging-11 in merge commit bd59d9a3d3.

Check out the triggered DDCI request.

If you need to revert this integration, you can use the following command: /code revert-integration -b staging-11