Should a support statement with flags get version_removed when unflagged?

[gsnedders]

Seemingly we don't currently have consensus here. Sometimes they get version_removed, sometimes they don't. We should have a policy here, and enforce it with a lint (at least in the case when the version_removed would align with version_added without a flag).

For example, api.AnimationTimeline has:

          "firefox": [
            {
              "version_added": "75"
            },
            {
              "version_added": "63",
              "flags": [
                {
                  "type": "preference",
                  "name": "dom.animations-api.timelines.enabled",
                  "value_to_set": "true"
                }
              ]
            }
          ],

Which results in Yari showing:

Whereas api.CanvasRenderingContext2D.createConicGradient has:

            "firefox": [
              {
                "version_added": "90"
              },
              {
                "version_added": "86",
                "version_removed": "90",
                "flags": [
                  {
                    "type": "preference",
                    "name": "canvas.createConicGradient.enabled"
                  }
                ]
              }
            ],

Which results in Yari showing:

[queengooborg]

In BCD, we use a version_removed for the flags when the flag itself has been removed, rather than when it's enabled by default. However, this isn't a defined policy, and I personally feel that it would be simpler just to mark the support behind a flag as removed once it's enabled by default. We should definitely plan a policy and document it.

[gsnedders]

See also #16287 which added a guideline here.

That said, given the guideline says:

Set version_removed to the earliest applicable version from these conditions. For example, if Chrome 90 enabled the flag by default, the feature could no longer be toggled off by disabling the flag in Chrome 96, and finally the flag was removed by Chrome 98, then set version_removed to 90 as it is the earliest applicable version.

How does this work with preview as a version? Do we treat preview as the earliest applicable version in all eternity, or do we change it following a release?

[queengooborg]

#16287 should probably have marked this issue closed, right?

In regards to preview, preview should always be considered the most recent (latest) version, since it's data for an upcoming/beta release.

[queengooborg]

I'm going to mark this as closed assuming that #16287 or #16637 has covered this.