dart-lang/sdk#48272 describes a proposal to eliminate the legacy .packages file that was replaced by package_config.json in the Dart SDK. In Flutter, we depend on this file in CoverageCollector via the packagesPath parameter.

package:coverage deprecated this parameter in dart-archive/coverage#370 (related issue dart-lang/tools#484) and replaced it with a dependency on the path to the package for which coverage should be computed. See this dependencies roll.

We should remove our dependency on this file in CoverageCollector and file bugs for any other uses of this file we discover.