There's a confusing naming inconsistency in OE-core...

The command to invoke the dev shell is:
bitbake <task> -c devpyshell

However, the prompt in the shell is "pydevshell".

Indeed, you see both names in the code:

$ git grep devpyshell
meta/classes/devshell.bbclass:def devpyshell(d):
meta/classes/devshell.bbclass:python do_devpyshell() {
meta/classes/devshell.bbclass:        devpyshell(d)
meta/classes/devshell.bbclass:addtask devpyshell after do_patch
meta/classes/devshell.bbclass:do_devpyshell[nostamp] = "1"
meta/conf/documentation.conf:do_devpyshell[doc] = "Starts an interactive Python shell for development/debugging"
scripts/oepydevshell-internal.py:histfile = os.path.expanduser("~/.oedevpyshell-history")

$ git grep pydevshell
meta/classes/devshell.bbclass:        oe_terminal("oepydevshell-internal.py %s %d" % (sname, pid), 'OpenEmbedded Developer PyShell', d)
meta/classes/devshell.bbclass:        ps1 = "pydevshell> "
scripts/oepydevshell-internal.py:    print('oepydevshell-internal.py: error: the following arguments are required: pty, pid\n'
scripts/oepydevshell-internal.py:          'Usage: oepydevshell-internal.py pty pid\n\n'
scripts/oepydevshell-internal.py:          'OpenEmbedded oepydevshell-internal.py - internal script called from meta/classes/devshell.bbclass\n\n'

It's probably easier to replace "pydevshell" by "devpyshell", so that the task name doesn't change.

Note that this will require a documentation update too.

I'll be happy to propose a patch but I need your opinions first.
Thanks in advance
Michael.