The `legacy` feature of ResourceLoaderSkinModule will be deprecated in the 1.36 release (see T89981)
In the 1.37 release Vector will drop use of the `legacy` feature. This will reduce the amount of bytes on the critical path of Vector.
This will also remove styling support for the elements `.mw-ajax-loader`, `.mw-small-spinner`
https://codesearch.wmcloud.org/deployed/?q=(mw-ajax-loader%7Cmw-small-spinner)&i=nope&files=&excludeFiles=&repos=
Repos that wish to continue to use these styles should copy across the style to their own repository. It would be preferable if such repos used their own class as well to avoid false positives in the above search result.
e.g.
```
.mw-ajax-loader {
background-image: url( images/ajax-loader.gif );
background-position: center center;
background-repeat: no-repeat;
padding: 16px;
position: relative;
top: -16px;
}
.mw-small-spinner {
padding: 10px !important; /* stylelint-disable-line declaration-no-important */
margin-right: 0.6em;
background-image: url( images/spinner.gif );
background-position: center center;
background-repeat: no-repeat;
}
```