Page Marker was introduced by ASUS as part of ZenUI 4.0, but the app has now found its way onto the Play Store. It might be a closed beta for now as the testing enrollment page isn't open for all, or it could only be compatible with select ASUS devices (none of my devices can get it and even Corbin's two ASUS tablets don't show as compatible), but the app is listed on the Play Store and we were able to grab the APK file for sideloading.
So what exactly is Page Marker? It's kind of like a middle ground between Chrome's built-in page downloader and the full-fledged Pocket service. The app only resides on your phone, so there doesn't seem to be a web component to it. When I installed it on my Nexus 5X, the icon didn't show in the app drawer, but I was able to start it up by sharing a page to it from Chrome. That launched the onboarding process and asked me to give it a few permissions such as drawing over apps and accessibility. That's because Page Marker works like a floating button that only shows up on top of Chrome.
Once tapped, it lets you download the current page you're viewing, preview it in an article form without any ads or superfluous elements, or open your entire Page Marker list. There, you can choose any article and view it in the clear reading mode, with tags, annotations, font size control, and a night mode switch. You can also save pages to your Google Drive.
If you're interested in giving Page Marker a go, you can check out if it's available for you on the Play Store or manually grab the file from APK Mirror. It seems to work well on my Nexus 5X so odds are good it might work on more than ASUS devices.