<style>
    .common-ligatures-disabled { font-variant-ligatures: no-common-ligatures; }
    .common-ligatures-enabled { font-variant-ligatures: common-ligatures; }
    .common-ligatures-normal { font-variant-ligatures: normal; }
</style>
<body style="font-size: 36px;">
    <div>
        <div class="common-ligatures-disabled">file</div>
        <div class="common-ligatures-normal">file</div>
        <div class="common-ligatures-enabled">file</div>
    </div>
    <div style="text-rendering: optimizelegibility">
        <div class="common-ligatures-disabled">file</div>
        <div class="common-ligatures-normal">file</div>
        <div class="common-ligatures-enabled">file</div>
    </div>
</body>