In my own text-info script:
With the caveat that the parasite doesn't exist until you save the file (so you won't find it on a freshly created text layer).
Code:
def text_info(img,layer):
parasites=None
try:
parasites=layer.parasite_list()
except Exception as e:
pass;
if parasites and 'gimp-text-layer' in parasites:
data=layer.parasite_find('gimp-text-layer').data
pdb.gimp_message('Text layer "%s": %s' % (layer.name,data))
else:
pdb.gimp_message('No text information found for layer "%s"' % layer.name)