EXPORT_PACKAGE_DEPENDENCIES: Add experimental feature gate

Some design concerns have been raised after trying the 3.29 release candidates. Avoid committing to a stable public interface for now.

Issue: #25767
Backport: release

changed milestone to %3.29.0

added workflow:in-review label

requested review from @ben.boeckel

assigned to @brad.king

changed title from Add experimental gate to EXPORT_PACKAGE_DEPENDENCIES features to EXPORT_PACKAGE_DEPENDENCIES: Add experimental feature gate

added 1 commit

• 873d2aa2 - EXPORT_PACKAGE_DEPENDENCIES: Add experimental feature gate

Compare with previous version

mentioned in issue #25767

mentioned in issue #25758 (closed)

added 1 commit

• 3a739d4d - EXPORT_PACKAGE_DEPENDENCIES: Add experimental feature gate

Compare with previous version

Warnings:

• Eligible for the 3.29.x branch.

The warnings do not need to be fixed, but it is recommended to do so.

Do: stage

added workflow:nightly-testing label and removed workflow:in-review label

resolved all threads

Do: merge

mentioned in commit 886333da

mentioned in commit b7c78e15

merged

removed workflow:nightly-testing label

mentioned in merge request !9507 (merged)