Remove PWA Category

[adrianaixba]

Issue tracking the removal of the PWA category

• deprecation warning banner
• remove the category from the json result
• remove/rearrange PWA audits
• ensure support for report PWA category rendering post removal
• remove references to documentation in codebase
• Get rid of ServiceWorker gatherer
• Get rid of Manifest/InstallabilityErrors gatherers and ManifestValues computed artifact
• unlist Lighthouse PWA documentation in the report
• clean up PWA Github issues

a nice have, but not a blocker for releasing this - would need some more investigation on this one.

• maybe include a no_pointless_service_worker audit

[adamraine]

Might be worth going through all of the issues marked "pwa" and either close or merge into this issue: https://github.com/GoogleChrome/lighthouse/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-desc+PWA+label%3Apwa

remove Lighthouse PWA documentation
remove references to documentation

We can remove references to documentation in v12.0, but old versions of Lighthouse will always link to the PWA documentation we have. For this reason, I don't think we should remove documentation completely. We should keep the https://developer.chrome.com/docs/lighthouse/pwa/ articles alive if you have the exact URL for an article, but you shouldn't be able to find Lighthouse PWA stuff just clicking through https://developer.chrome.com/.

[connorjclark]

Can we unlist the doc from other pages / doc search instead? We should keep the old links working for old versions of lh

[brendankenny]

We definitely want those URLs to last forever. We have a banner we've used in the past to indicate up front that the audit is no longer maintained and when that happened:

https://developer.chrome.com/docs/lighthouse/performance/first-cpu-idle/

Not sure how others feel, but I also prefer to have some navigable path to docs that exist, though it shouldn't be prominent. I made a metrics graveyard at the bottom of the performance section with links to retired metrics, for instance. A whole category is slightly different, but we could e.g. make a separate subpage for retired categories or whatever.

[adrianaixba]

I feel good about keeping these docs forever, adding a "deprecated" banner, and just unlisting/have them be absent when navigating through developer.chrome.com.