Bitcoin Improvement Proposals (BIPs) are formal documents that outline new features or changes to the Bitcoin protocol. They serve as a way for developers and the community to propose, discuss, and refine ideas that could enhance the functionality or security of the network. Each BIP is assigned a unique number and goes through a review process before being accepted or rejected. BIPs can cover a wide range of topics, including technical specifications, governance processes, and best practices. They are essential for maintaining transparency and collaboration within the Bitcoin ecosystem, allowing stakeholders to contribute to the ongoing development of the cryptocurrency.