The freestanding RB scrambler has been scrapped for the last couple of SketchUp versions.
It is no longer available.
You must now register as a developer with Trimble and upload your RBZ [a re-suffixed ZIP file] containing just one 'loader - "xxx.rb" - and one "xxx" subfolder [containing the extension's main code files and other helper files] to here:
https://extensions.sketchup.com/en/developer_center/extension_signature
This gives then you the option of leaving everything as RB files, or encrypting any RB files in the "xxx" subfolder [the 'loader' RB is never encrypted].
There are also 2 options for encrypting.
RBS is the older format that is known to have been cracked and offers only obfuscation and not full protection of your IP, however it's advantage is that if will work in all SketchUp versions from v8 up to v2017.
RBE this newer format is more robust and not [yet] hacked. Its disadvantage is that it only works with v2016 and newer versions. If you opt for including both encrypted versions in your RBZ, then the RBS version exposes your IP anyway.
Depending on the options chosen, after only a few minutes or processing a modified RBZ is then available for you to download and redistribute yourself.
When submitting your RBZ it will now always ne 'signed'.
Two special files are added to the RBZ's subfolder - these 'hash' the RBZ's contents. If the two files are removed or changed, OR any of the sensitive files to which they refer are different from the initial submission, then that loading extension will report itself as 'unsigned' etc in the Extension Manager and will not load is the more restricted loading-policies [although most users will stick with 'unrestricted' anyway!]. The 'sensitive' files in RBZ are RB/RBS/RBE/HTM/HTML/JS/CSS.
Having your own RBZs 'signed' is not as onerous as making a submission to the EWH.
If your intention is to publish at the EWH then you also need to register separately as a developer there. You then submit your unsigned/unencrypted RBZ to them. It takes considerably longer than the self-certification option. There are also much stricter coding requirements etc and your submission can be rejected for not following their best practice. This is explained more fully on their site...