Issue #3494035: use attributes for plugin discovert

Closes #3494035

added 3 commits

• d770af88 - migrate source
• 1177e616 - MigrateDestination
• 2ea312fe - commas

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added 6 commits

• 2ea312fe...3022d348 - 4 commits from branch project:2.x
• 4248c00a - Merge remote-tracking branch 'origin/2.x' into 3494035-convert-plugin-discovery
• f3b66509 - rebase

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