diff --git a/hcl2template/types.hcl_post-processor.go b/hcl2template/types.hcl_post-processor.go
index 6698b3f5a..0afec4d4b 100644
--- a/hcl2template/types.hcl_post-processor.go
+++ b/hcl2template/types.hcl_post-processor.go
@@ -10,6 +10,10 @@ import (
 	"github.com/zclconf/go-cty/cty"
 )
 
+// HCL2PostProcessor has a reference to the part of the HCL2 body where it is
+// defined, allowing to completely reconfigure the PostProcessor right before
+// calling PostProcess: with contextual variables.
+// This permits using "${build.ID}" values for example.
 type HCL2PostProcessor struct {
 	PostProcessor      packer.PostProcessor
 	postProcessorBlock *PostProcessorBlock
diff --git a/hcl2template/types.hcl_provisioner.go b/hcl2template/types.hcl_provisioner.go
index 795497874..3ea1e35dc 100644
--- a/hcl2template/types.hcl_provisioner.go
+++ b/hcl2template/types.hcl_provisioner.go
@@ -10,6 +10,10 @@ import (
 	"github.com/zclconf/go-cty/cty"
 )
 
+// HCL2Provisioner has a reference to the part of the HCL2 body where it is
+// defined, allowing to completely reconfigure the Provisioner right before
+// calling Provision: with contextual variables.
+// This permits using "${build.ID}" values for example.
 type HCL2Provisioner struct {
 	Provisioner      packer.Provisioner
 	provisionerBlock *ProvisionerBlock