Accessibility: Video block placeholder image missing Alt

[rnunez80]

Accessibility Issues
WCAG 2.1 Level A
Alternative (alt) text is read to users utilizing screen readers. Alternative text should be provided to describe what is present in the image so that users who are unable to see have an equal experience as sighted users. Quick tip: If the image is being utilized as a link with no other text, the alternative text should be the location of the link. If the image is of words, the alternative text should be the words contained in the image.
Impact: critical
Violations
WCAG 2.1 Level A: 1.1.1 Non-text Content
Section 508: 1194.22 (a) Text equivalent for non-text elements
Element Location
.computer.mobile.tablet:nth-child(1) > div > .video.block.align > .video-inner > .\31 6:9.embed.ui > .placeholder

Element Source

Failure Summary
Fix any of the following: Image does not have an alt attribute. To markup the image as decorative, override the semantics by adding role="none" or role="presentation"

[stevepiercy]

@maniksharma424
please read and follow Contributing to Plone and First-time contributors.

[rotavio]

We've just found out this issue while running a11y tests.
The Embed component from SemanticUI does not have a way to change props for the placeholder image.

Are there any plans to fix this issue?

If we choose to customize it in our project, what would be the native or "volto way" of doing this?