Good news: This has fixed a problem I had with being unable to run a minecraft server in a jail, which I posted about in reddit:
https://www.reddit.com/r/Minecraft/comments/aky2ba/fresh_1132_world_crashes_due_to_watchdog_running/
Bad news: The "Save" button appears grayed out when trying to edit settings on a new jail. While testing the above, I could not enable procfs via the GUI, because the save button was unavailable.
I had to use Chrome's inspect feature to change the element myself so I could click it.
<button _ngcontent-c20="" class="btn btn-block btn-warning mat-button mat-primary" color="primary" mat-button="" type="submit" disabled=""><span class="mat-button-wrapper">Save</span><div class="mat-button-ripple mat-ripple" matripple=""></div><div class="mat-button-focus-overlay"></div></button>
Changed the "disabled" to "enabled" and was able to save the config.
The page doesn't seem to be properly detecting when something is changed, to update the save button.