MobileFrontend has the following PNG files (without the SVG counterparts). Let's convert them to SVG's:
./resources/mobile.overlays/back-ltr.png
./resources/mobile.search/search-content.png
./resources/mobile.special.mobilediff.styles/negative.png
./resources/mobile.special.mobilediff.styles/neutral.png
./resources/mobile.special.mobilediff.styles/positive.png
./resources/mobile.startup/images/error.png + ./resources/mobile.references/images/error.png
This will solve various issues (e.g. T142391) and makes the user experience enjoyable for browsers that support SVGs.
SVG versions ready to be replaced
{F7946368}
{F7946369}
{F7946370}
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= A/C
[] Remove PNG assets in favour of SVGs
[] Generate the PNGs via the ResourceLoaderImage module
[] Use mw-ui-icon and mw-ui-icon-small where necessary to style the icon elements
= PNG assets for references
{F7884044}
{F7884070}
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{F7884046}
{F7884176}