Yes custom template file will ve overwritten with an update. To avoid this issue, follow these steps:
– Create a directory named download-manager inside your active theme directory
– Now copy the files you want to modify from /src/{ComponentDir}/views dir to /{active-theme}/download-manager/ dir.
– Customize template file(s) in {active-theme}/download-manager dir as per your need
– Keep dir structure, means, a file from /src/Packages/views/link-templates dir should go to /{active-theme}/download-manager/link-templates dir.
Please check and let me know if you require any further assistance.
Regards