What is .TM file extension?
Structured text document created with TeXmacs, a graphical LaTeX editor developed for Unix systems; may include text, graphics, mathematical formulas, graphs, and interactive content.
TeXmacs documents can be exported as .XML, .PS, .PDF, and Scheme files.
You can see a list of software programs here on easyfileopener.org that can open this file type so that you don’t need to search for it on the web. You can then open your file with this extension using a software listed below.