Miscellaneous

Get executed QGIS Python code

In the QGIS menu: Processing/History.

In a plugin (from QGIS 3.28): Advanced/Copy as Python Command

Set projection and ellipsoid

project = QgsProject.instance()
...
crs = QgsCoordinateReferenceSystem.fromEpsgId(4326)
project.setCrs(crs)
project.setEllipsoid('EPSG:4326')

See the available process and scripts

for alg in QgsApplication.processingRegistry().algorithms():
    print("{}:{} --> {}".format(alg.provider().name(), alg.name(), alg.displayName()))

Using QGIS Buttons in Python Code

eMenu = iface.viewMenu()
eMenu.actions()[12].trigger()