Browser tools will find different issues
The text in this paragraph fails colour contrast. All 3 tools should find it.
Missing alt text
All 3 tools should find that the following image of a sleepy kitten does not have any alternative text.
Skipped heading level
All 3 tools should also find that the heading for this section is a h5 and it should be a h2.
ARC Toolkit and Axe DevTools should find that this paragraph is using an invalid role of 'potato'.
This paragraph is also using an invalid role of 'paragraph'. But, only ARC Toolkit will find it. Axe will ignore it.
Wave wont see either as errors and will mark them as features and you'll need to figure out yourself that they're not valid.
Bad link text
The link after this paragraph is a common accessibility failure as it does not provide enough context. Wave will mark it as being suspicious but Axe DevTools and ARC Toolkit will ignore it.Read more
ARC Toolkit will pick links up if you use terminology like Click here to view file, but it just shows how varied the tools are.
Axe DevTools literally doesn't care about either.
ARC will warn that there is no navigation landmark. There isn't a nav menu on this page, so we don't have to fix it. But on most pages you would have a nav element, so it's good that it flags it.
It will also flag that there is no bypass blocks method. Again, because there is no header or navigation menu on this page it doesn't matter. But in most cases you'd want to have one.
Axe and Wave will not warn you of either of these issues.
ARC Toolkit will point out that a linebreak is used at the end of this section, even though its a valid use of one.
Axe DevTools and Wave will not care.