[Glass] Silly question: what is "GLASS"?

[Pieter Nagel via Glass]

There seems to be some ambiguity as to what the term GLASS refers to.

On http://seaside.gemtalksystems.com/ it refers to GemStone, Linux,
Apache, Seaside, and Smalltalk. In other words it just seems to be a
catchy overarching name for the practice of providing web systems by
running Seaside on GemStone (as opposed to, say, using Ruby on Rails). In
that sense of the word, it seems to me when you've successfully loaded 
Seaside on some version of GemStone, you've got GLASS.

But then there's GLASS1, the Metacello project, published at
github://glassdb/glass:master/repository, which is apparently something
newer than GLASS,which is published elsewhere, even though GLASS1's
repository is not called github://glassdb/glass1, somewhat confusingly.

I've always asssumed that GLASS/GLASS1 is just a collection of low-level
dependencies needed to load Seaside on GemStone. But isn't that also what
Grease is, in a way?

The GLASS readme says how to load it, but not what it *is*, or when you
may want to load it.

On the other hand, the Seaside 3.1 installation instructions say to use
GsUpgrader to upgradeGrease, and no mention of using it to upgradeGLASS1.

So if GLASS1 isn't needed for Seaside, what is it for?

Sorry for such a silly question by a member of a mailing list that is,
after all, called "GLASS" ;-)