Avoid a notice in trackback_rdf() if user agent is not set.

props joostdevalk.
fixes #27374.
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git-svn-id: http://core.svn.wordpress.org/trunk@27357 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Revert [27203], restore JIT color scheme stylesheets. Restores [27111].

fixes #27175. see #20729.

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git-svn-id: http://core.svn.wordpress.org/trunk@27358 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Smooth out some display and race condition issues with the media modal loading spinner. props kadamwhite, gcorne. see #24859.

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git-svn-id: http://core.svn.wordpress.org/trunk@27359 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Ensure the correct model is selected when editing an image from gallery mode. props gcorne. fixes #27363.

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git-svn-id: http://core.svn.wordpress.org/trunk@27360 1a063a9b-81f0-0310-95a4-ce76da25c4cd
In `wp.media.view.AttachmentFilters`, when creating its inner HTML content, pass `filter.text` via `.html( str )` instead of `.text( str )` to allow more formatting options. 

Props tlovett1.
Fixes #25010.


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git-svn-id: http://core.svn.wordpress.org/trunk@27361 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Account for `preload="metadata"` in audio and video shortcodes when multiple versions of the same `<source>` appear on the page by appending a query arg to "cache-bust" passed sources. The query arg is used to make the sources "unique." They will still be cached by the browser and won't bust the cache on every request.

Fixes #26779.


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git-svn-id: http://core.svn.wordpress.org/trunk@27362 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add a class property to `wp.media.view.MediaDetails` called `instances` that is incremented every time the class is invoked. This mimics what happens in the shortcodes: the sources receive an incremented cache-buster so that the browser won't ignore the file when `preload="metadata"` is set.

See #26779.


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git-svn-id: http://core.svn.wordpress.org/trunk@27363 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Avoid a notice in `get_the_category_by_ID()` when `is_wp_error( $term )` is false but `$term->name` is not set. Clarify the `@return` value of `get_category()` and `get_tag()` which return the same possible types as `get_term()`, which they wrap.

Props ericmann, SergeyBiryukov.
Fixes #25429.


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git-svn-id: http://core.svn.wordpress.org/trunk@27364 1a063a9b-81f0-0310-95a4-ce76da25c4cd
The Image Editor should apply changes to custom image sizes by checking `$_wp_additional_image_sizes` for `$size` in `wp_save_image()` before arbitrarily going to the options table.

Props Otto42, SergeyBiryukov.
Fixes #19889.


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