basics on homotopy cofibers #3338

Job	Run time
nix	2m 25s
opam-build (supported, ubuntu-latest)	5m 10s
build (supported)	3m 24s
opam-build (latest, ubuntu-latest)	4m 34s
quick-build (supported, ubuntu-latest)	3m 17s
build (latest)	3m 19s
quick-build (latest, ubuntu-latest)	3m 20s
opam-build (dev, ubuntu-latest)	3m 31s
quick-build (dev, ubuntu-latest)	2m 41s
build (dev, --warnings)	2m 51s
doc-coqdoc	0s
coqchk	0s
doc-dep-graphs	0s
doc-alectryon	0s
doc-timing	0s
install	0s
deploy-doc	0s
delete-artifacts	4s
	34m 36s

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