The build log contains many chatty lines beginning with a verb like "Assembling", "Compiling", etc.

Anomalously, the verb running is sometimes preceded by '# '. Here is the reduced summary of these informative messages.

$ grep -E '^(# )?[A-Za-z]*ing ' build/linux-x86_64-normal-server-release/build.log | sed -e 's/ing.*/ing/' | sort -u
Assembling
Compiling
Creating
Generating
Ignoring
Importing
Linking
Making
Running
# Running
Unzipping
Updating
Using
Verifying

I've attached the uncompressed grep results for the "chatty" messages.