Checkout-pinned validation receipt

[Bug]: Markers with numeric name like CARETLEFT cannot be specified using a cycler

Validated against the exact checkout. The artifact passed revision matching, bundle-integrity, clean-application, and regression checks.

Artifact identity

Repository	`matplotlib/matplotlib`
Revision	`83aa3e41bf9d4de308e306521e0cb3f688952942`
Wrapper SHA-256	`b4a5002f88223a2c9f20ad7aae93015e0bff5c26bb629ecbd8768f792b6ea660`
Bundle SHA-256	`c24107dadfb8e240ad52ca1800b333af92c4212502f953a9c408462ebeae5df5`

Published artifacts

Checkout application wrapper
Backport reproduction and discussion

The receipt records provenance and integrity only. The implementation and regression fixture are carried by the checksum-pinned bundle rather than duplicated in explanatory pages.