Personal data are so if they can be linked to an identified or identifiable person.<p>So in itself an URL would need to not only contain information that may be deemed personal but also information to identify that person.<p>In the case of logs I think the criteria are most likely met when considering that time, IP address, and metadata such as URLs are often collected to stored together. These 3 pieces of information <i>together</i> may then most likely become (sensitive) personal data.