If you’re using the Canarian version of Chrome, you may have noticed the reading list icon that hangs on the right side of the bookmarks bar, just below your profile picture and the main settings button. This is a new feature from Chrome 89, hidden by default in the standard release, but accessible via a flag, and enabled by default in Chrome 91
If you are in Canary and have your bookmarks bar visible, right-click on an empty area in the bar. Near the bottom of the right-click menu are a number of options, which now include “View Reading List.” Click this entry to uncheck and hide the read list button. To make it appear again, just do the same thing the other way around.
This is a great option for those on smaller laptops or tablets, where horizontal space is at a premium. Although the reading list itself is available via flags in beta and full release of older versions, this is not the right-click option to hide it quickly.
There is never any guarantee of what Google will or will not promote in Chrome, but this seems like a simple and natural enough extension of existing functionality that it will probably be retained in the transition. These are the kind of small adjustments that can even jump ahead of version releases, so you can see it in Chrome before 91 gets to the general release branch in a few months.