Specification

https://www.w3.org/TR/css-align-3/#justify-block

Description

The justify-self property is supposed to work on block-level elements (in addition to absolutely positioned elements and grid items).
This also means that justify-items works on block containers.

Because this is a somewhat recent addition to what justify-self applies to, it ought to be its own new feature, similar to https://web-platform-dx.github.io/web-features-explorer/features/align-content-block/

Documentation

https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/Properties/justify-self

Browser support

Chromium only.