The purpose
As shown in the article below, group information is lost when a .sif
file saved in Inkscape is opened in Synfig Studio.
However, it’s difficult to find and manipulate the necessary objects without group information. Therefore, this article introduces how to carry over group information to Synfig Studio.
Save Layer
In short, by making them layers instead of groups, layers in Synfig Studio are treated as groups.
Convert group to layer
Right-click the group you want to convert in the “Layers and Objects” tab. Then, select “Group to Layer” from the menu that appears.

If the icon changes from the left one to the right one, it’s been converted to a layer.

Convert group to layer

Save and Load
For instructions on saving from Synfig Studio and opening in Inkscape, please refer to the article below.
Refference
SVG Import - Synfig Animation Studio
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