Glossary

Terms as buckroot uses them. Where Buildroot and Buck2 use the same word for different things, both are listed.

Term	Meaning
action	one command Buck2 runs with declared inputs and outputs; a package action runs make <pkg> in a view
action key	the digest of an action's command, declared inputs and declared environment; equal keys mean a reusable result
artifact	an action's output: for a package, one tarball with its per-package/<pkg>/{host,target} tree and stamps
auto.conf	the file Buildroot's prepare step reads to skip Kconfig; each config slice ships one
cache salt	a string added to every action's environment so a measured cell misses the cache once; see ADR-0010
cell (Buck2)	a root of Buck2 rules and targets (root, prelude); unrelated to the matrix
cell (matrix)	one variant x mode combination in a results table, run cold and (for cache modes) warm
closure	a package's dependencies, direct and transitive; its view contains their directories
cold / warm	a run that finds nothing in the cache / a run after buck2 clean that can be served from it
delta	what a package added to host/ and target/, as opposed to the complete merged tree
early cutoff	Buck2 stops rerunning downstream actions when an action reruns but produces identical output
extra view	directories a package's .mk reads without depending on them; declared in extra_view
golden	the plain-make reference build a Buck2 result is compared with
heavy	a package that gets a weight so it runs alone
manifest	the JSON list of every path in an image with type, mode, owner, link target, size and hash
native	a package built by Buck2 actions instead of make <pkg>; see Wrapped and native
owners	the map from each BR2_* symbol to the directories that declare it (//br2/generated:owners)
PPD	Buildroot's per-package directories (BR2_PER_PACKAGE_DIRECTORIES): one output tree per package
slice	the part of .config a package can see; see Views and config slices
stamp	a .stamp_* file by which Buildroot's make knows a package step is done
strict / dev	whether the toolkit's scripts are action inputs; see ADR-0009
target tuple	the toolchain's name (aarch64-buildroot-linux-gnu), which names the sysroot directory
variant	wrapped or native
view	the allow-list of directories a package action can see inside its mount namespace
virtual package	a package name that several providers implement (libgles, skeleton); chosen by BR2_PACKAGE_PROVIDES_*
weight	the number of local CPU slots an action occupies
wrapped	a package built by Buildroot's own make <pkg> inside a Buck2 action