From the Tk chat:

dgp	I think something is wrong with fossil annotations.

dgp	Looking at [http://core.tcl.tk/tcl/ci/4683efaee9ca414d4ff2690ba19b3b7a6d1afaed]
dgp	it's a small patch to tclListObj.c.  Introduces only five new lines.

dgp	Then open [http://core.tcl.tk/tcl/artifact/31d1cfe5711802cce0d1ac7fa7a48c4c0607a63f]
dgp	to see what tclListObj.c created by that checkin looks like.
dgp	Then click the [annotate] link to reach [http://core.tcl.tk/tcl/annotate?checkin=4683efaee9ca414d&filename=generic/tclListObj.c]
dgp	I would expect to see only those five new lines marked with 4683efaee9 but I see many more than that.

dgp	starting with lines 21 & 22 or so which are nowhere near the patch.

dgp	Conversely, those five new lines are marked with something else
dgp	403736bc07 - which is the same patch, but the checkin applying it to core-8-5-branch.
dgp	I'd have expected annotations to trace back the primary parent links, not the merges.