The purpose of this link is to point to the project's homepage, which in this case would be http://padre.perlide.org/.
An owner or member of the repo should be able to update this by clicking the "Edit" button that appears for them to the right of the description (see https://stackoverflow.com/a/21649064/4896937 for an illustration).
Near the top of the GitHub repo (Code tab), next to the description is a link that currently just points to https://github.com/.
The purpose of this link is to point to the project's homepage, which in this case would be http://padre.perlide.org/.
An owner or member of the repo should be able to update this by clicking the "Edit" button that appears for them to the right of the description (see https://stackoverflow.com/a/21649064/4896937 for an illustration).