Apache Guacamole is a clientless remote desktop gateway. It gives users access to remote computers and virtual machines from a web browser, using the standard protocols VNC, RDP and SSH, so no plugin or client software is needed. It has two main parts: a web application that handles the interface, authentication and authorisation, and guacd, a backend service that translates the native protocols into the Guacamole protocol. Target machines can stay isolated behind the gateway and need not be reachable from the internet. Guacamole is software you install and run yourself.
Guacamole is open source under the Apache License 2.0 and has been a top-level project of the Apache Software Foundation since 2017. The foundation is a nonprofit in the United States, run almost entirely by volunteers; commercial support is offered by third-party companies. Because you host it yourself, your organisation decides where the gateway and its session traffic reside, including within the EU.