A standalone Kotlin library for removing tracking parameters from URLs using JSON-defined rules. It loads a ruleset (currently embedded as `clearurls.json`) and applies transformations to strip known tracking parameters, redact URLs, and normalize queries. The library is self-contained (only depends on Kotlin stdlib) and can be extracted into a new project with minimal adaptation. It demonstrates non-obvious skill in implementing a performant, rule-based URL sanitizer with support for provider-specific rules, wildcards, and pattern matching.

A custom expression evaluation engine with its own bytecode-like opcodes (see `OpCodes.kt`) for evaluating rules on URL and intent contexts. It supports comparisons, string operations, regex matching, control flow (if/else), and access to engine run context (URL, app role, etc.). Expressions are serializable via protobuf, allowing persistence and potential exchange. The evaluator is designed as a tree of `Expression` nodes with a `BlockExpression` for sequences. Despite being part of the larger engine feature, the core evaluation logic is isolated and could be reused in any Kotlin project needing a lightweight, embeddable rule evaluator.

A set of interfaces and models that define a generic backup/export pattern for any repository. `ExportableRepository` declares `export()` and `import()` using typed export models. The `ExportModel` provides a `type` discriminator and a serializer. This pattern allows any data store to be easily included in the app's backup/restore flow. The design is clean, decoupled from the specific backup UI, and could be extracted as a reusable library for any Android app needing structured data export/import.