On 16b5ee0efb5592f78faeffa07048bfe741331a18 `org-clocking-buffer` was removed as a symbol. That symbol is still being referenced throughout the current(4d463ee4baf8a7ce8b7c633149a9452bc70ef557) `org-clock.el` file. Emacs : GNU Emacs 28.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.5, cairo version 1.16.0) of 2020-12-25 Package: Org mode version 9.4.3 -- Eduardo Bellani -- datarisk.io