RabbitMQ - RabbitMQ is an open source message broker software.
MacDown - MacDown is an open source Markdown editor for OS X, released under the MIT License.
Ethereum - Ethereum is a decentralized platform for applications that run exactly as programmed without any chance of fraud, censorship or third-party interference.
Frost - An open API for Blockchain timestamping
Hyperledger - Hyperledger is a multi-project open source collaborative effort hosted by The Linux Foundation, created to advance cross-industry blockchain technologies.
Typora - A minimal Markdown reading & writing app.