This was an incredibly useful tool back in the day.
Unfortunately Onyx Technologies seems to have gone out of business and some other company with nothing to do with development tools has taken over the name and domain (www.onyx-tech.com), which would make this clearly abandonware in my estimation.
If anyone has a copy of this tool, please upload it!
onyx-tech.com does appear to lead to a different company. However onyxtech.com apparently leads to the Spotlight Memory Debugger that you refer to...
It also appears to be still for sale for PPC Macintosh, which would negate any abandonware status.
Hmmm... All the links I could find (here at MacTech, and here at MacNews, and most importantly within the demo version of the application itself) specified www.onyx-tech.com.
Looking at the wayback machine, it looks like the website suddenly appeared on www.onyxtech.com in 2001, but even the webpages still refered to www.onyx-tech.com. Before this, the domain belonged to some other entity also calling itself Onyx Technology, then it ended up in the hands of someone running a website calling itself "The Third Rail", before finally hosting pages taken from www.onyx-tech.com.
But what's even more interesting is that Onyx Technology, Inc. was dissolved on Sept. 22, 2000, about seven months before the website showed up at www.onyxtech.com. Here are the records from the Florida Department of State Division of Corporations. It looks like the corporation went out of business by allowing itself to lapse and become inactive. So, Onyx Technology, Inc. no longer exists as a legal entity.
It looks like www.onyxtech.com is a doppleganger website, claiming to represent a corporation that no longer legally exists.
So, I think that clarifies that the *legal* status of Spotlight is abandonware since its copyright holder no longer exists. However, it's possible that Onyx Tech was always just a one-man corporation and the fellow just couldn't afford to maintain the corporate entity. He might very well be the one running the website at the new domain, trying to make whatever he can to scrape by with, and I don't feel like being a jerk and dropping a dime to report him for doing business as his defunct corporation.
I think there might a difference in this situation between what we *can* do and what we should do. At least until we can determine with more certainty whether the guy who wrote this is the one trying to sell it at the new domain. I'm willing to respect all the hard work and ingenuity the human author put into this, even if I'm not *legally* required to. I'm going to try making contact by email and see whether "the lights are on but nobody's home".
I've sent a request for a serial to activate the demo of Spotlight at onyxtech.com to see if there's any response.
Whenever I try to download either the QC or Spotlight demos from www.onyxtech.com, all I get is a "200 OK" http response (I had to bring up the "web console" in firefox to even see that response code.). No demo file downloads. The pdf order forms will download but that's it.
Anyone else seeing this happen?
No. I DL'd from this page clicking the link labeled "HERE" in the page. Its why I typed above that I'd sent off for the demo's serial (still waiting)
Its an "HQX" formatted file, so if you're using a Mozilla variant browser e.g firefox etc, then you should right-click the link and choose to Save the link as... otherwise it'll likely go fubar (long standing bug in mozilla browser engine, re HQX files).
OK, thanks for pointing that out. I never had any problem like that dl'ing hqx files from this site, so I didn't think twice about needing to use the "save as" command.
30 hrs+ since sending request for demo license. No response so far... waiting for the spam to come flooding in 
[Update] Well over 72 hours since sending a request off for a license to a demo of this utility software... and no response to date.
I'm now of the opinion that the OP, Captain Obvious is correct, this is abandonware and should be uploaded.
It'll be a rare software, but may be of use to some if the full version (not the demo) is uploaded and archived here.
I bought a copy of Spotlight when it was first announced as a "Developer Release I" (ie a beta or perhaps Alpha version) in 1998. The readme stated that the "Golden Master" would be released "shortly".
2 years later the Golden Master v1.0 was actually delivered. I wrote to the Developer a few times in between DR1 and GM. It turns out that Onyx was a 2 person company (Brooks Bell and someone else). They bought Spotlight from yet another person and tried to market it as their own. The product displayed enormous promise but was so buggy it was unusable. I tried it on even the simplest piece of bad code (reference a nil pointer) and it would crash the computer.
In a message, Brooks finally admitted that Spotlight was the greatest mistake he ever made.
Gary
Huh, I had almost the exact opposite experience from yours regarding the stability and usefulness of Spotlight. The company I was working for in the late 90's had a rather poorly written legacy application that totalled about a hundred thousand lines, and Spotlight did a bangup job finding all sorts of problems in the code. I forget which version we had there, and I remember having a few hicups when I first started using it, but they turned out to be our own program seriously screwing things up to begin with.
The DR1 release (along with DR2 and DR3) were unusable. The GM (v1.00) was ok and DID give me some useful results. I still use it occasionally
Gary.
I finally figured out how to upload to the Garden. It turns out that Classilla can naviate the Garden upload pages successfully.
I've uploaded this app from my collection. The serial number is included in the SIT file. The file unpacks to an installer file. The Installer messes a bit with your System Folder so run it with caution.
