OK, apology in order – my temperature sizzled, and I jumped to the conclusion that they were being added in the core, and not as a filter in the default theme (which is a damn good place for them!).
Now, if only you could tear half the other activity presentation stuff out of the core – or leastways create some more granular template tags / functions – so that we’re not stuck PHP unlocking those monolithic activity strings. That would be really lovely.
Apologies again, bit of humble pie for me, and @nuprn1 .. thanks for pointing out the filter