The built-in Search Results module is not WCAG 2.0 compliant. Here is an example message explaining the violation:
"This third-party content is inaccessible for screen reader and keyboard users.
Ensure this content is accessible for screen reader and keyboard users. Examples of some inaccessible features are the table is lacking scope attributes, elements receive focus in an illogical order, links are lacking valid HREF attributes, and expandable controls not being indicated to screen reader users. However, there are likely other accessibility issues in addition to those listed here. Consider reaching out to the vendor of this application requesting information on a version of their tools that meets WCAG 2.0/2.1 level AA. Please feel free to contact us to discuss remediation options."
Please note that customizing core files falls beyond our scope of support. However, customization work can be requested via platinum support plans. To proceed with this option, please create a support ticket to get more information.
This situation has been reported to the development team to be reviewed for future improvements.