Protocol Buffers - Google's data interchange format
Lean's OpenWrt source
qBittorrent BitTorrent client
Detectron2 is FAIR's next-generation platform for object detection and segmentation.
Bitcoin Core integration/staging tree
H2O - the optimized HTTP/1, HTTP/2, HTTP/3 server
Telegram for Android source
C++ Library Manager for Windows, Linux, and MacOS
BCC - Tools for BPF-based Linux IO analysis, networking, monitoring, and more
FlatBuffers: Memory Efficient Serialization Library