Virtel Web Suite is a software package from Syspertec Group, a French software company in Saint-Cloud, that makes mainframe applications accessible over the web. The modular solution replaces 3270 terminal emulation with browser access, lets a screen redesign tool present existing applications as modern web interfaces, and an integration module turns mainframe transactions into web services. This applies to environments such as CICS, IMS, Natural and TSO on IBM z/OS. An organisation can thus modernise step by step without rewriting or replacing its applications.
Syspertec Group is headquartered in France, and its website names no foreign parent. Virtel is software that you run inside your own mainframe environment, so data stays where you operate the mainframe. It does depend on IBM mainframe platforms, which is a separate point in your sovereignty assessment. Ask about support terms, the roadmap and access to source code or escrow arrangements for long-lived, business-critical applications.