Kdenlive is the strongest free editor you can run without signing anything. It is GPL-3.0 software from KDE, the non-profit behind the Linux desktop suite, and the license is the whole point for adult work: the GPL explicitly affirms "unlimited permission to run the unmodified Program." No EULA, no terms of service, no cloud agreement, no clause anywhere about what your footage may contain.
Nothing phones home. There is no account and no activation, and KDE's application privacy policy commits telemetry to be opt-in and disabled by default, with no data that could identify the device or its user. Your rushes never touch a vendor server because there is no vendor server.
It is a real NLE, not a toy. Proxy editing, multicam, a full effects stack, and releases on Windows, macOS, Linux and BSD. The official manual asks for 8 CPU cores and 16GB RAM for 4K work, with proxy and preview-resolution workflows for getting 4K done on less. There is no watermark and no paid tier; the project runs on donations.
The trade-offs are the usual open-source ones. Support is community forums rather than a vendor ticket queue, and the interface has less polish than the commercial NLEs. If you want the same free-and-unrestricted posture in a smaller tool, Shotcut is the same license story with a simpler editor.
Bottom line. The best license posture in this category, attached to the more capable of the two GPL editors. Start with the editing workflow guide and cut on this without a licensing worry.
