It's a Hybris JSP tag. See the following files:
- /yacceleratorstorefront/web/webroot/WEB-INF/common/tld/ycommercetags.tld
- /yacceleratorstorefront/web/src/de/hybris/platform/yacceleratorstorefront/tags/TestIdTag.java
TestIdTag
is described as:
Tag that generates a wrapping div with the specified id. The id is
suffixed with an incrementing counter for the page request to ensure
that it is unique. The wrapper divs can be turned on and off via a
configuration property.
The test ID can be used for testing. Without IDs, it may be difficult to use testing automation tools like Selenium, which can look for HTML elements via element ID.
It's also related to this project property:
# Turn on test IDs for selenium and smoke tests (not for production)
#yacceleratorstorefront.testIds.enable=true
As reichhart commented, and as the property comment above mentioned, this should not be enabled in Production, as it may become a security issue.