In this new change, he has updated adduser and shadow packages to change the home directories default permission from 755 (rwxr-xr-x) to 750 (rwxr-x—) when it is created using either adduser or useradd utility.
This simply means if you install Ubuntu 21.04 from scratch and create new users, its home directories will no longer be readable and executable by other users on the same system, which was earlier world-readable by default.
However, a user or administrator can still update home folder permissions if they want to make the directory public or accessible to others.
If you do not know, the argument of the home directory being too open for all was raised back in 2006.
But now, after more than 14 years considering Ubuntu’s significant customer and userbase in public cloud and server spaces, and having better security, Ubuntu team has decided to stop creating world-readable home directories starting from Hirsute Hippo.
It’s also worth noting that the new proposal received no opposition.
As Alex Murray also says from a regression point-of-view, the change in default behaviour will not affect any permissions on existing installs or on upgrades.
If you want to try Ubuntu 21.04 Hirsute Hippo before its stable release, you can download its daily updated ISO image from here.
Note: Daily ISO can contain bugs, so it’s highly recommended not to use it for production.