strange css class

This big gob of code. What does it mean? Surely there is a reason. Because UNA is fast and efficient. Thank you.

class="no-htmlimports no-flash no-proximity sizes transferables applicationcache blobconstructor blob-constructor cors customelements no-customprotocolhandler customevent dataview eventlistener geolocation history no-ie8compat json notification postmessage queryselector serviceworker svg templatestrings typedarrays websockets no-xdomainrequest webaudio cssescape supports target no-microdata mutationobserver passiveeventlisteners picture es5array es5date es5function es5object strictmode es5string es5syntax es5undefined es5 es6array arrow es6collections generators es6math es6number es6object promises es6string no-devicemotion no-deviceorientation filereader beacon no-lowbandwidth eventsource fetch xhrresponsetype xhr2 speechsynthesis localstorage sessionstorage websqldatabase svgfilters urlparser urlsearchparams getusermedia websocketsbinary atobbtoa atob-btoa no-framed no-sharedworkers webworkers no-contains no-contextmenu cssall willchange classlist documentfragment audio canvas canvastext contenteditable emoji olreversed no-userdata no-vml webanimations webgl adownload audioloop canvasblending todataurljpeg todataurlpng no-todataurlwebp canvaswinding bgpositionshorthand multiplebgs csspointerevents cssremunit rgba preserve3d dataset hidden outputelem progressbar meter ruby template no-time texttrackapi track unknownelements no-capture fileinput formattribute placeholder sandbox no-seamless srcdoc imgcrossorigin srcset inputformaction input-formaction inputformenctype input-formenctype inputformmethod no-inputformtarget no-input-formtarget scriptasync scriptdefer no-stylescoped inlinesvg textareamaxlength videocrossorigin videoloop videopreload no-ambientlight hashchange inputsearchevent datalistelem csscalc cubicbezierrange cssgradients opacity csspositionsticky csschunit cssexunit hsla bdi xhrresponsetypearraybuffer xhrresponsetypeblob xhrresponsetypedocument xhrresponsetypejson xhrresponsetypetext svgclippaths svgforeignobject smil svgasimg no-hiddenscroll mathml no-touchevents unicoderange unicode checked displaytable display-table fontface generatedcontent hairline cssinvalid lastchild nthchild cssscrollbar siblinggeneral subpixelfont cssvalid cssvhunit cssvmaxunit cssvminunit cssvwunit details oninput formvalidation mediaqueries hovermq pointermq pointerevents fileinputdirectory textshadow no-batteryapi no-battery-api crypto no-dart fullscreen no-forcetouch gamepads intl pagevisibility performance pointerlock no-quotamanagement requestanimationframe raf no-vibrate no-webintents no-lowbattery getrandomvalues backgroundblendmode objectfit object-fit no-regions no-wrapflow no-filesystem no-requestautocomplete no-speechrecognition bloburls peerconnection no-datachannel matchmedia ligatures cssanimations csspseudoanimations appearance backdropfilter backgroundcliptext bgpositionxy bgrepeatround bgrepeatspace backgroundsize bgsizecover borderimage borderradius boxshadow boxsizing csscolumns csscolumns-width csscolumns-span csscolumns-fill csscolumns-gap csscolumns-rule csscolumns-rulecolor csscolumns-rulestyle csscolumns-rulewidth csscolumns-breakbefore csscolumns-breakafter csscolumns-breakinside no-cssgridlegacy cssgrid ellipsis cssfilters flexbox flexboxlegacy no-flexboxtweener flexwrap cssmask no-overflowscrolling cssreflections cssresize scrollsnappoints shapes no-textalignlast csstransforms csstransforms3d no-csstransformslevel2 csstransitions csspseudotransitions userselect bx-media-desktop blobworkers no-dataworkers exiforientation apng jpeg2000 webpalpha webpanimation webp no-jpegxr webp-alpha webp-animation webp-lossless datauri indexeddb audiopreload indexeddb-deletedatabase"