Compliance exports (inc. private channel and/or DM conversations in which the exporter was not participating) have never been a part of free plans, and that hasn't changed in the last year.
Initially they had no export function at all. When they added it, they did so for paid plans only (and with an unpreventable notification to everyone on the workspace that an export was just triggered). They've evolved it since then for higher plans like Enterprise Grid w/o notifications and integration into Data Loss Prevention (DLP) tools, but it's still never touched free plans.
You can read about the initial announcement at https://www.theverge.com/2014/11/24/7255199/slack-alters-pri... . I would suspect that what you're positing to be a "complete history dump" from free Slack workspaces are from archive bots, which don't have the ability to eavesdrop on conversations in which they weren't already present.
Initially they had no export function at all. When they added it, they did so for paid plans only (and with an unpreventable notification to everyone on the workspace that an export was just triggered). They've evolved it since then for higher plans like Enterprise Grid w/o notifications and integration into Data Loss Prevention (DLP) tools, but it's still never touched free plans.
You can read about the initial announcement at https://www.theverge.com/2014/11/24/7255199/slack-alters-pri... . I would suspect that what you're positing to be a "complete history dump" from free Slack workspaces are from archive bots, which don't have the ability to eavesdrop on conversations in which they weren't already present.