I am using NoteTab Light as my text editor to create local webpages and Firefox mainly as the browser, with "Web Developer Tools" activated when there is an error.

There is a strange set of script tags injected into the html head code block, seen when viewed with the Web Developer Tools. I wasn't able to copy it (option locked/grayed out), but someone else was able to:

<script>(function(){class RuffleMimeType{constructor(a,b,c){this.type=a,this.description=b,this.suffixes=c}}class RuffleMimeTypeArray{constructor(a){this.__mimetypes=[],this.__named_mimetypes={};for(let b of a)this.install(b)}install(a){let b=this.__mimetypes.length;this.__mimetypes.push(a),this.__named_mimetypes[a.type]=a,this[a.type]=a,this[b]=a}item(a){return this.__mimetypes[a]}namedItem(a){return this.__named_mimetypes[a]}get length(){return this.__mimetypes.length}}class RufflePlugin extends RuffleMimeTypeArray{constructor(a,b,c,d){super(d),this.name=a,this.description=b,this.filename=c}install(a){a.enabledPlugin||(a.enabledPlugin=this),super.install(a)}}class RufflePluginArray{constructor(a){this.__plugins=[],this.__named_plugins={};for(let b of a)this.install(b)}install(a){let b=this.__plugins.length;this.__plugins.push(a),this.__named_plugins[a.name]=a,this[a.name]=a,this[b]=a}item(a){return this.__plugins[a]}namedItem(a){return this.__named_plugins[a]}get length(){return this.__plugins.length}}const FLASH_PLUGIN=new RufflePlugin("Shockwave Flash","Shockwave Flash 32.0 r0","ruffle.js",[new RuffleMimeType("application/futuresplash","Shockwave Flash","spl"),new RuffleMimeType("application/x-shockwave-flash","Shockwave Flash","swf"),new RuffleMimeType("application/x-shockwave-flash2-preview","Shockwave Flash","swf"),new RuffleMimeType("application/vnd.adobe.flash-movie","Shockwave Flash","swf")]);function install_plugin(a){navigator.plugins.install||Object.defineProperty(navigator,"plugins",{value:new RufflePluginArray(navigator.plugins),writable:!1}),navigator.plugins.install(a),0<a.length&&!navigator.mimeTypes.install&&Object.defineProperty(navigator,"mimeTypes",{value:new RuffleMimeTypeArray(navigator.mimeTypes),writable:!1});for(var b=0;b<a.length;b+=1)navigator.mimeTypes.install(a[b])}install_plugin(FLASH_PLUGIN);})();</script>

Does anyone know what this is, let alone why someone would be using shockwave, flash, or swf?