The word "Issues" encompassed both bugs and feature requests.

If the meaning is blank, then the meaning is implicit in the name (contribute a clarifying definition if you believe the meaning is not self-evident).

If the meaning is a "?", then Felix did not immediately know the meaning of the label and does not think it is self-evident.

TAGS LABELS	Meaning
AREA TAGS
A-an-interesting-project	A self-contained independent project
A-android	Related to Android mobile device OS
A-attributes	Issues with Rust meta-data attributes
A-build	Issues bootstrapping rust compiler and runtime
A-codegen	Issues with rustc code generator
A-concurrency	Scheduler, tasks, plus other concurrency idioms
A-debuginfo	Debug meta-data for integration with gdb
A-destructors	Destructors (static lifetime based; not finalization)
A-diagnostics	Error reporting (some overlap with A-lint)
A-docs	Issues with tutorials, manuals, and API docs
A-driver	Issues with wrapper around rustc/rustdoc/etc
A-ffi	Foreign Function Interface i.e. interop with C/C++
A-freebsd	Related to FreeBSD operating system
A-frontend	Issues with rustc frontend (librustc::front::*)
A-grammar	Grammar spec (not implementation; see A-parser)
A-iOS	Related to Apple iOS device operating system
A-infrastructure	Mozilla-hosted services: buildbot, website, etc
A-instrumentation	Rust library / object code instrumentation
A-libs	Rust standard and contributed libraries
A-linkage	Crate format+tooling for dynamic/static linking
A-lint	Warning categorization and tooling in rustc
A-linux	Related to Linux operating system
A-llvm	Related to LLVM IR and code-generation library
A-macos	Related to Apple Mac OS X operating system
A-metadata	Crate-embedded data for reflection/compilation
A-parser	Parser impl. (not specification; see A-grammar)
A-pkg	Issues with package management e.g. rustpkg
A-plugin	compiler plugins and their infrastructure
A-pretty	Pretty-printing rust source via rustc --pretty
A-regions	Lifetime semantics; borrow-checker (aka borrowck)
A-resolve	Identifier/name resolution
A-runtime	Task scheduler, memory management, core I/O
A-rustdoc	API documentation extraction and generation tool
A-rusti	rusti is a REPL-like dynamic Rust interpreter
A-syntaxext	syntax extensions aka macros i.e. macro_rules!
A-testsuite
A-tools	For Rust user: syntax highlighting, profiling, etc
A-traits	Trait system provides bounded polymorphism + OOP
A-typesystem	Rust's static type system, type check (aka typeck)
A-unicode	Unicode handling, parsing or conversion
A-versioning	Version numbers/handling for language + libraries
A-visibility	Visibility/privacy: item pub/priv and their access
A-windows	Related to Microsoft Windows operating system
BLOCKER TAGS
B-RFC	Blocked on a Request-for-Comment
B-clarifying	put label description here
B-reproduce	Blocked on a need to reproduce problem locally
EFFORT TAGS
E-easy	Effort: easy
E-hard	Effort: hard
E-mentor	?
E-needtest	Effort: requires a unit test to be closed
E-tedious	Effort: tedious
IMPACT TAGS
I-ICE	Importance: error internal to rustc
I-cleanup	Importance: Internal source code cleanup
I-completion	Importance: fill gaps in existing implementation
I-crash	Importance: Rust runtime/program is crashing
I-enhancement	Importance: Potential tools/language enhancement
I-nominated	Importance: Nominated for a milestone
I-papercut	Importance: easily fixable usability bug
I-slow	Importance: slow (in compile or running time)
I-wishlist	Importance: would be nice but can do without
I-wrong	Importance: behavior does not match specification
PRIORITY TAGS
P-backcompat-lang	Priority: Language backward-compatible
P-backcompat-lib	Priority: Library backward-compatible
P-high	Priority: High
P-low	Priority: Low
uncategorized tags
metabug	Collects several related issues together