From what I'm reading there this is a measure of mass flow rate of gas, expressed as volume per minute at some standard volume and pressure. Which makes some sense, you need those two parameters to be fixed so you can measure mass by volume.
And then I realized the OP article uses it for a fluid liquid 😂
The major difference is compressibility. Generally, liquids are practically incompressible. So just knowing the mass flow rate and density, volume flow rate can be calculated. It's not so simple for gases
First of all: Sorry, I made a mistake yesterday. I ment to say liquid but translated it wrong in my head
Now to your question, they are similar in some aspects, that's what makes gasses and liquids both be considered fluids, so fluid dynamics apply to both for example.
The difference is how much the molecules in the liquid or gas interact: A lot in the liquid, not significantly in most gasses under standard conditions.
And the things is, the SLPM measure apparently relies on a characteristic of ideal gasses, that one mol of gas particles under standard conditions always takes a fixed volume 22.41 l. So now I'm confused why they would use it for hydraulic fluid, which sounds like a liquid to me.
Volume changes based on temperature and pressure. So when we reference volume measurements like for flow rates, we typically do the math to adjust those to standard temperature and pressure. Standard pressure is 1 atm but standard temperature varies based on who you're talking to because of competing standards. It's usually 25 C or 20 C.
When we want to reference the non temperature and pressure corrected volume, we append actual to it so that people know what the measurement is. Some people don't do that and that causes confusion for others using their work if the reading is standard or actual.