In reply to Eric Mesa.

They don't work. To the degree that they do work, they mostly offer functionality that is already duplicated by user's own technology.

This particular overlay also commits the cardinal sin of labeling tools by disability, rather than according to what they do. For example, if you turn on the "Visually Impaired" mode, that's actually a high contrast mode; which is only relevant if your visual impairment benefits from high contrast. This kind of presumptive labeling is ineffective at best (because it makes it difficult to find what tool might actually help you, should you need it), and offensive at worst.

But the reality is that overlay tools are a misdirection of resources: if a user needs high contrast, large fonts, or other tools, they need those on all websites, and they need a solution that's their tool, in their control, with their settings - and the majority of users already have that in their assistive technology.