In December 2023, SiriusXM changed their web player software. Ever 
since, it has run poorly on my X200, which cannot use GPU acceleration 
in web browsers. Similarly, their use of infinite-looping CSS and SVG 
animations cause all browsers to crash after a few hours (as reported 
through the /r/SiriusXM subreddit), and usually max out CPU and RAM 
utilization. Their web software engineering team does not recognize 
these problems because they are ignorant.

Thankfully in Firefox, a user may define their own stylesheet, which 
can alleviate the deficiencies in the SiriusXM web player. This 
functionality may be enabled through `about:config` by setting the 
`toolkit.legacyUserProfileCustomizations.stylesheets` property to 
`True`.

Then, a chrome/userContent.css file may be created within the Firefox 
profile with the following content, which will block CSS animations, 
transitions, transformations, and most-critically the SVG animation on 
a channel's play button.

* {
    -o-transition-property: none !important;
    -moz-transition-property: none !important;
    -ms-transition-property: none !important;
    -webkit-transition-property: none !important;
    transition-property: none !important;
    
    transition: none !important;
    translate: none !important;
    
    -o-transform: none !important;
    -moz-transform: none !important;
    -ms-transform: none !important;
    -webkit-transform: none !important;
    transform: none !important;
    
    -webkit-animation: none !important;
    -moz-animation: none !important;
    -o-animation: none !important;
    -ms-animation: none !important;
    animation: none !important;

    --animation-stroke: none !important;
    --animation-background: none !important;

    -webkit-animation-iteration-count: 1 !important;
    -moz-animation-iteration-count: 1 !important;
    -o-animation-iteration-count: 1 !important;
    -ms-animation-iteration-count: 1 !important;
    animation-iteration-count: 1 !important;
}

[class*="animation"] svg {
    display: none !important;
}