When I use the css property align-items, I cannot see any visual difference with the value of flex-end or value of end.
What i
One value (end) is defined in the CSS Box Alignment specification, and is intended to apply to multiple box layout models (block, table, grid, flex, etc.)
The other value (flex-end) is defined in the CSS flexbox specification, and is intended to apply only to flex layout.
With the Box Alignment spec, the W3C is attempting to establish a universal language for the alignment of boxes in CSS. Eventually, the Box Alignment values will supersede the particular values defined in flex, grid and other specs.
For example:
end will be used instead of flex-endcolumn-gap will be used instead of grid-column-gapMany Box Alignment values are already in use across major browsers. But full implementation is still a ways off, so it's still safer to use flex-end instead of end (and then count on long-term support for legacy names).
Here's an illustration from the Box Alignment spec:
§ 8.3. Legacy Gap Properties: the grid-row-gap, grid-column-gap, and grid-gap properties
The Grid Layout module was originally written with its own set of gutter properties, before all such properties were unified into the existing
row-gap/column-gapnaming. For compatibility with legacy content, those legacy property names must be supported as aliases:
grid-row-gapmust be treated as a shorthand for therow-gapproperty
grid-column-gapmust be treated as a shorthand for thecolumn-gapproperty
grid-gapmust be treated as a shorthand for thegappropertyIn all three cases, the legacy properties must take the same grammar as the property they are aliasing, and just "forward" the value to their aliased property.