Which additional library is NOT required when installing Zabbix on Linux?

When installing Zabbix on Linux, it's important to understand the dependencies required for the system to function correctly. The choice of libxml2 being the additional library that is NOT required is accurate because Zabbix does not explicitly depend on libxml2 for its core functionalities.

Libpcre is necessary for regular expression support, which Zabbix uses to process strings and patterns. Libevent is crucial for asynchronous I/O, which helps Zabbix efficiently handle multiple requests and manage performance. Zlib is required for compression and decompression tasks, especially for data storage and communication, which improves both performance and efficiency.

In contrast, while libxml2 is a commonly used library for handling XML data, Zabbix does not require it for its basic operations. Therefore, it is not listed as a mandatory library for installation, making libxml2 the correct choice in this context.