on top of the normal Eglot behaviour. From the manual:
"When you visit a file under the same project, whether an existing or a
new file, its buffer is automatically added to the set of buffers managed by
Eglot, and the server which supports the buffer’s major-mode is notified
about that. Thus, visiting a non-existent file /home/joe/projects/fooey/lib/y.foo
in the above example will notify the server of the *.foo files’ language
that a new file was added to the project, even before the file appears
on disk. The special Eglot minor mode is also turned on automatically
in the buffer visiting the file."
João