The PegaWAI:07-10-01 ruleset ships with Pega 7.1.9
I can send the ruleset to you if you need it.

To answer to the What part of the question, PegaWAI ruleset is added to the application to make the application Accessibility friendly. We need to add the ruleset to the production ruleset list of the application rule and check the checkbox Enable Accessibility Add On so that Pega can take care of the accessibility of the application.

1)  Initiatives are under way to mandate that disabled users have equal access to Internet resources, including the guidelines issued by the Web Accessibility Initiative (WAI) of the World Wide Web Consortium (W3C) and, in the United States, the amendments to Section 508 of the Rehabilitation Act of 1973 or the Americans with Disabilities Act (ADA).

2)  PegaWAI ruleset contains additional accessibility features. These include alternate versions of certain controls, additional JavaScript to alter behavior for accessibility, field values that enhance callout in screen readers, and when rules that act as switches for these different features.

3)  To enable the PegaWAI ruleset we need to import it into our application.  

     We then add the ruleset to the Production Ruleset list on our application.

     Finally, we add the ruleset to the access groups of developers and users needing accessibility features and controls.  On the access group’s Advanced tab, we enter the ruleset in the Production Rulesets list and click the Enable accessibility add-on checkbox.

4) Please refer "DESIGNING ACCESSIBLE APPLICATIONS" lesson in "UI SPECIALIST (7.1)" course for more information

The PegaWAI accessibility Ruleset now ships with the Pega 7 media in the ResourceKit directory.

Use the Import Wizard to install the ruleset by specifying the ZIP file:

<your_Pega7_Product>\ResourceKit\AccessibilityFramework\pxWAI_<your_version>.zip

How could i get the PegaWAI Ruleset ?