Is it a dedicated montage file format, store significate in the "internal" memory, how much Motion Sequences can we store if it's internal memory ?

I'm sure it is a Montage format - what else can use Motion Sequences? - How many exactly is unknown at this point (there is probably a limit but the number must be huge). You can store and load unlimited Motion Sequences.

Each Performance can have their own Motion Sequences - more to come as we go along. Numbers at this point would not mean anything to you.

I understand most part of the screen but what are "prm1" with the selection of number 9, "prm2" with number 3 ?

"prm1" and "prm2" influence the CURVE of the PULSE you have selected. If prm1 = 5 you have a linear curve - for each unit increase input you get a unit increase output.
When "prm1" = 9 you get more movement late in the curve, prm1 = 0 you get more movement early in the curve.
"prm2" will influence the intensity of the movement. prm2 only appears on specific selected Curves (if a second control parameter is applicable). On PULSE B on you see only "prm1" because STANDARD does not require an intensity - it is simple and linear.

These will be totally obvious when you move the parameters, you will see the shape of the CURVE animate in the screen to indicate what you have applied.

There are 18 PRESET Pulses to choose from or you can create 32 of your own USER Pulse curves.
When you go to LOAD SEQUENCE there is are Preset Motion Sequences, or you can search your USB drive for those you have created.
I believe you can store 256 Motion Sequences in on-board memory.

I understand for the "step" i think 1 to 8 the pictures that represant the motion sequence "tilt sine" and "standard" one in forward, the other on reverse, what are the 'icons" for step 9 to 16, is it "link" to the "prm" or it seams to are "tilt sine" ?

No, but a good guess, without having a manual...

There are 16 Steps available in a Motion Sequence. The screenshot you show is showing LANE 1 of the Motion Sequence (there can be four Lanes in a Motion Sequence) and 8 Motion Sequences in a PERFORMANCE. You are viewing Motion Sequence #7. The top line indicates that it includes all 16 steps (CYCLE = 16). Amplitude and Smooth are self explanatory when you can hear the results. Amplitude increase the overall intensity and Smooth rounds out the result or sharpens it to a cutting edge!!

The UNI and BI - POLAR simply select whether the result are always above the centerline or whether they oscillate back and forth between positive and negative - this will be determined when you choose the destination for this Motion Control... Obviously PAN would be bipolar... where VOLUME would be unipolar.
Pan takes advantage of values above and below a centerpoint, while Volume cannot be less than 0 (or better said, values for volume below zero are zero).

PULSE A - the curve TILTED SINE was chosen from the 18 Preset shapes. The prm1=9, prm2= 3 cause this to increase late with the intensity shown.
PULSE B - the curve STANDARD was chosen and is "reversed" and prm=5 (linear) for each unit decrease input, you get a unit decrease output.

The first 8 Steps being selected is just how this window works (two groups of 8), you can select 9-16 and edit those. This allows you to use the CS1-8 to set the Amplitude of each step - quickly and intuitively.

I was truly amazed at the depth and ease with which you can create these Motion Control Sequences and how quickly you can put them together. They can be manipulated to give them feel, much like you would manipulate the timing of an arpeggio. You can UNIT MULTIPLY these so that if 16 steps equals 100% in 4/4 time this is a measure.

If UNIT MULTIPLY is set to 50% the Motion Sequence will be double time the tempo (take place in one-half the amount of time it takes to play a measure).
If UNIT MULTIPLY is set to 200% the Motion Sequence will be half time of the tempo (take place in twice the amount of time it takes to play a measure).
Motion sequences can be set 6400% so you can have radical or very subtle motion within your Montage sound.

Whaou what an amazing answer, thank you so much Bad Mister and even without the reference manual you give us deep informations with lot of details, very very great.
I think i will have lot of explanations to done on Moessieurs when i will receive the Montage just for the Motion sequences.
And there will be also Motion control, FM-X ......; it's huge 😉