Emacs-Guix provides major and minor modes for highlighting build logs.
So when you have a file with a package build output—for example, a
file returned by
guix build --log-file … command
(see Invoking guix build in The GNU Guix Reference Manual),
you may call M-x guix-build-log-mode command in the buffer
with this file. This major mode highlights some lines specific to
build output and provides the following key bindings:
Move to the next build phase.
Move to the previous build phase.
Toggle (show/hide) the body of the current build phase.
Toggle (show/hide) the bodies of all build phases.
There is also M-x guix-build-log-minor-mode which also provides the same highlighting and the same key bindings as the major mode, but prefixed with C-c. You may find this minor mode useful for shell buffers (see Interactive Shell in The GNU Emacs Manual). It can be enabled there like this:
(add-hook 'shell-mode-hook 'guix-build-log-minor-mode)