Bug 1707590 - Part 3: Add feature gate for JXL r=tnikkel,fluent-reviewers,preferences-reviewers

Differential Revision: https://phabricator.services.mozilla.com/D113360

toolkit/components/featuregates/Features.toml

@@ -31,6 +31,17 @@ bug-numbers = [1443863]
 is-public = {default = false, nightly = true}
 default-value = {default = false, nightly = false}
 
+[media-jxl]
+title = "experimental-features-media-jxl"
+description = "experimental-features-media-jxl-description"
+description-links = {bugzilla = "https://bugzilla.mozilla.org/show_bug.cgi?id=1539075"}
+restart-required = false
+preference = "image.jxl.enabled"
+type = "boolean"
+bug-numbers = [1539075]
+is-public = {default = false, nightly = true}
+default-value = false
+
 [web-api-inputmode]
 title = "experimental-features-web-api-inputmode"
 description = "experimental-features-web-api-inputmode-description"

toolkit/locales/en-US/toolkit/featuregates/features.ftl

@@ -20,6 +20,12 @@ experimental-features-media-avif =
     .label = Media: AVIF
 experimental-features-media-avif-description = With this feature enabled, { -brand-short-name } supports the AV1 Image File (AVIF) format. This is a still image file format that leverages the capabilities of the AV1 video compression algorithms to reduce image size. See <a data-l10n-name="bugzilla">bug 1443863</a> for more details.
 
+# The title of the experiment should be kept in English as it may be referenced
+# by various online articles and is technical in nature.
+experimental-features-media-jxl =
+    .label = Media: JPEG XL
+experimental-features-media-jxl-description = With this feature enabled, { -brand-short-name } supports the JPEG XL (JXL) format. This is an enhanced image file format that supports lossless transition from traditional JPEG files. See <a data-l10n-name="bugzilla">bug 1539075</a> for more details.
+
 # The title of the experiment should be kept in English as it may be referenced
 # by various online articles and is technical in nature.
 experimental-features-web-api-inputmode =