Thank you for the information. But I sill don't understand why this error occurs.
I build Sage in the Docker container using the Sage repo as follows.
git checkout a83e25136481efb99d9cb8c00dde3065c0d04894
make
Then I got the following error message
(if I use the commit f26b322f76034b8122603cbc4c7b02d4011f0cd9, then building succeeds).
cd ../.. && sage-logger -p './sage --docbuild --no-pdf-links all html ' logs/dochtml.log
[dochtml] Setting permissions of DOT_SAGE directory so only you can read and write it.
[dochtml] /home/docker/sage/local/bin/python: No module named interpreters.wrapper_rdf; 'sage_setup.docbuild' is a package and cannot be directly executed
Makefile:1064: recipe for target 'doc-html' failed
make[2]: *** [doc-html] Error 1
make[2]: Leaving directory '/home/docker/sage/build/make'
Makefile:887: recipe for target 'all' failed
make[1]: *** [all] Error 2
make[1]: Leaving directory '/home/docker/sage/build/make'
real 71m12.794s
user 232m3.108s
sys 19m54.532s
***************************************************************
Error building Sage.
The following package(s) may have failed to build (not necessarily
during this run of 'make all'):
The build directory may contain configuration files and other potentially
helpful information. WARNING: if you now run 'make' again, the build
directory will, by default, be deleted. Set the environment variable
SAGE_KEEP_BUILT_SPKGS to 'yes' to prevent this.
Makefile:16: recipe for target 'all' failed
make: *** [all] Error 1