Hello and welcome here;
The "x1=k2" style for argument slot marking is used for showing both
the slot number (here x1), and the etymology of that slot, or in
other words from which argument slot of which of the source words
that have been used to construct the lujvo.
In the case of samyzilkei, which is a lujvo coming from the tanru
{skami zi'o kelci}: "x1=k2 is a video game on platform x2=s1", we
have the x1 slot marked with the etymological information "k2", for
"the second slot of the gismu that is used for building this lujvo
and begins with the letter K", so {kelci} here, and we have the x2
slot marked with "s1", so the first slot of the source gismu
beginning with S, so {skami} in this case.
So the first slot of {samyzilkei} is a {se kelci}, thus a game, and
the second slot comes from {skami}, so a computer.
•
http://jbovlaste.lojban.org/help/definitions.html
As for "tityzme: g1 is a melon of cultivar g2":
This notation is similar to the previous paradigm, but the slot
number information (x1= / x2= / x3= ...) is missing, which can be
even more confusing.
Personally, I like neither of those etymological paradigms, I prefer
to use the simple and clear x1/x2/x3/... notation, even for lujvo. I
think that if the etymology of the lujvo is deemed important, it
should be put in the notes or in a specific field, but not clutter
the definition.
Many beginners have complained about those notations. Except the
page I've linked above, there doesn't seem to be an explanation of
those notations that is readily accessible and easy to find from the
main page of Jbovlaste.
mi'e la .ilmen. mu'o