XDA Developers tore down the app, and found some interesting strings in it. Pure Mode will be possible to activate after you put four fingers on the screen, and spread them outward.
You will be able to reverse this action by pull the fingers inwards. What does it do, though? Well, it's possible that the provided information is not 100-percent accurate, but it seems to have something to do with hiding desktop objects.
OnePlus Launcher is set to bring forth 'Pure Mode', and its functionality is still a mystery
So, there are two options, essentially. First, it can be a simple mode that offers essential icons on the display. Icons for phone, messages, your messenger of choice, or something else.
If this ends up being true, this could be a part of Zen Mode. Zen Mode, as most of you know, is OnePlus' digital wellness mode, pretty much.
On the flip side, 'Pure Mode' could have something to do with the desktop mode. You can now activate the desktop mode, but only through the Developer Options. This gesture could be used to hide all open floating windows to show the desktop.
Now, it's possible that 'Pure Mode' is something else, entirely, of course. These are the best guesses so far, though, and they make the most sense. There's not much info to go on at this point.
'Pure Mode' will probably make its way to OnePlus Launcher in a future beta build. OnePlus Launcher v4.5.4 is a beta version of the app, by the way, not a stable build.
OnePlus Launcher v4 introduced a revamped Recents menu
As already mentioned, OnePlus Launcher received some interesting features in the last couple of months. OnePlus Launcher v4 (stable), brought forth a new Recents menu.
Well, it's not entirely new, but it is revamped, and it offers some new features. It added icons underneath app previews for easy switching between them.
OnePlus Launcher v4.5.2, on the other hand, suggested that a system-wide search is coming to the app as well. That search will allegedly allow you to search for everything, including messages, contacts, and so on.
OnePlus Launcher also adopted the swipe down gesture to open Shelf quite recently. That is the same gesture you use to open the notification shade. You can choose which one you'll use, so you can still open the notification shade by using it. All in all, OnePlus is working hard on improving its Launcher, it seems.