The first issue can be easily fixed, just change: https://searchfox.org/mozilla-central/rev/ec806131cb7bcd1c26c254d25cd5ab8a61b2aeb6/browser/themes/shared/customizableui/panelUI.inc.css#1116 to `float: inline-end`. The second issue could be a bit trickier, see bug 1539633. Mirroring this image will mirror also the shield icon. Probably another SVG file needed here? Or, simply mirror this one and in bug 1539633 make sure to mirror all the rest.
Bug 1572492 Comment 2 Edit History
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The first issue can be easily fixed, just change: https://searchfox.org/mozilla-central/rev/ec806131cb7bcd1c26c254d25cd5ab8a61b2aeb6/browser/themes/shared/customizableui/panelUI.inc.css#1116 to `float: inline-end`. The second issue could be a bit trickier, see bug 1539633. Mirroring this image will mirror also the shield icon. Probably another SVG for RTL is needed here? Or, simply mirror this one and in bug 1539633 make sure to mirror all the rest.