Thanks for getting in touch! Octopus does indeed log configuration changes! You can check out the audit log in your web portal under the Configuration > Audit page which provides details of the changes made, when and who made the change. Changes to step templates, variable sets and environments are logged, along with other information. You can check out our auditing documentation page for some more details. https://octopus.com/docs/administration/auditing
Don't hesitate to reach out if you have any further questions.