Column-level security in Snowflake is implemented through Role Access Policies. These policies allow administrators to control access to specific columns of a table or view based on the role of the user accessing the data. By applying a role access policy to a column, administrators can ensure that sensitive information remains secure, and only users with the appropriate roles can view or query the data in that column. This feature enhances the security model by providing fine-grained access control at the column level.
References:
* Snowflake Documentation: Implementing Column-level Security

The command list @mystage; is used to view the list of files that have been uploaded to an internal stage in Snowflake. The list command displays the metadata for all files in the specified stage, which in this case is mystage. This command is particularly useful for verifying that files have been successfully unloaded from a Snowflake table to the stage and for managing the files within the stage.
References:
* Snowflake Documentation on Stages
* SnowPro Core Certification Study Guide

A cached MFA token is valid for up to four hours. https://docs.snowflake.com/en/user-guide/security-mfa#using-mfa-token-caching-to-minimize-the-number-of-prompts-during-authentication-optional

Row level security in Snowflake is available starting with the Enterprise edition. This feature allows for the creation of row access policies that can control access to data at the row level within tables and views