Final answer:
A screen reader is a software tool that can assist web developers in checking their online content for accessibility issues.
Adherence to WCAG is crucial for making web content accessible to those with disabilities, and feedback from users should inform ongoing enhancements.
Therefore, the correct answer is: option 'screen reader'
Step-by-step explanation:
Software that includes screen readers and automated accessibility testing tools and can help a web developer check online content for accessibility issues of people with disabilities.
Providing informative titles and headings, ensuring proper contrast ratios, as well as offering descriptive alt text for images are some of the practices outlined in these guidelines.
When creating or evaluating content, developers and authors should aim to improve accessibility, and be responsive to feedback from users with disabilities or those using assistive technologies.
Engaging with the community to upgrade platforms, such as OpenStax, or integrating feedback to improve materials like lab manuals in LibreTexts, are examples of ongoing efforts to enhance accessibility.