As the timeline below shows, I forgot to add prior to commit and produced two checkins ...4a and ...3d. Then checked out ...97, repeated the change and committed with --allow-fork ...85. How can I get rid of checkins ...4a and ...3d?
user@PC:~/blinky$ fossil timeline
=== 2019-11-18 ===
17:00:08 [199f536985] *CURRENT* Move LED functions to BSP (user: user tags: trunk)
16:45:55 [b44070073d] Move LED functions to BSP (user: user tags: trunk)
16:44:03 [8e1bd6364a] Move LED functions to BSP (user: user tags: trunk)
15:35:02 [b9c7685997] *FORK* blah blah
15:16:11 [d1629aa3fa] Initial commit (user: user tags: trunk)
14:39:08 [7fe2388931] initial empty check-in (user: user tags: trunk)
+++ no more data (6) +++
PS: stumbled upon Rebase Considered Harmful, explaining the downside of "cleaner history".